Question 1

An electric bulb is connected to a 220 V generator and draws a current of 0.50 A. What is the power of the bulb?

Accepted Answer

Correct Option: A. Solution: The power of the bulb is calculated using $P = VI = 220 	imes 0.50 = 110$ W.

Question 2

A circuit consists of a 6 V battery connected in series with a 2 Ω resistor and a 4 Ω resistor. What is the total current flowing through the circuit?

Accepted Answer

Correct Option: D. Solution: The total resistance in series is $R = 2 \Omega + 4 \Omega = 6 \Omega$. Using Ohm's law, $I = \frac{V}{R} = \frac{6 	ext{ V}}{6 \Omega} = 1 	ext{ A}$.

Question 3

An electric heater rated at 1000 W is used for 30 minutes. How much heat energy is produced by the heater?

Accepted Answer

Correct Option: B. Solution: The power of the heater is 1000 W, and it is used for 30 minutes, which is 1800 seconds. The heat energy produced is given by $P 	imes t = 1000 	imes 1800 = 1,800,000 	ext{ J}$.

Question 4

Which of the following factors does NOT affect the resistance of a conductor?

Accepted Answer

Correct Option: D. Solution: The resistance of a conductor depends on its length, material, and temperature, but not on its color.

Question 5

A circuit consists of a 10 Ω resistor connected in series with a 5 Ω resistor and a battery of 15 V. What is the current flowing through the circuit?

Accepted Answer

Correct Option: A. Solution: The total resistance in the series circuit is $R = 10 \Omega + 5 \Omega = 15 \Omega$. Using Ohm's Law, $I = \frac{V}{R} = \frac{15 V}{15 \Omega} = 1 A$.

Question 6

An electric heater of resistance $44 \, \Omega$ draws $5 \, A$ from the service mains for $2$ hours. Calculate the rate at which heat is developed in the heater.

Accepted Answer

Correct Option: B. Solution: The power $P$ is calculated using $P = I^2 R$. Substituting $I = 5 \, A$ and $R = 44 \, \Omega$, we find $P = (5)^2 	imes 44 = 1100 \, W$. The heat developed in 2 hours is $P 	imes t = 1100 	imes 2 = 2200 \, W$.

Question 7

If a 12 V battery is connected in series with resistors of $0.2 \, \Omega$, $0.3 \, \Omega$, $0.4 \, \Omega$, $0.5 \, \Omega$, and $12 \, \Omega$, what is the current through the $12 \, \Omega$ resistor?

Accepted Answer

Correct Option: A. Solution: The total resistance $R_t = 0.2 + 0.3 + 0.4 + 0.5 + 12 = 13.4 \, \Omega$. Using Ohm's law, $I = \frac{V}{R_t} = \frac{12}{13.4} \approx 0.8 \, A$.

Question 8

A circuit consists of a $12 \Omega$ resistor connected to a $24$ V battery. If the resistance is doubled, what happens to the current in the circuit?

Accepted Answer

Correct Option: C. Solution: According to Ohm's Law, $I = \frac{V}{R}$. If the resistance is doubled, the current is halved.

Question 9

Which of the following devices utilizes the heating effect of electric current for its operation?

Accepted Answer

Correct Option: A. Solution: The electric heater is a device that utilizes the heating effect of electric current to produce heat.

Question 10

Two lamps, one rated $100 \, W$ at $220 \, V$, and the other $60 \, W$ at $220 \, V$, are connected in parallel to an electric mains supply. What current is drawn from the line if the supply voltage is $220 \, V$?

Accepted Answer

Correct Option: B. Solution: The total power of the lamps is $100 \, W + 60 \, W = 160 \, W$. The current drawn from the line is $I = \frac{P}{V} = \frac{160 \, W}{220 \, V} = 0.73 \, A$.

Question 11

A resistor with resistance $R$ is connected to a voltage source of $V$ volts. If the current flowing through the resistor is $I$ amperes, according to Joule's law of heating, what is the heat produced in the resistor in time $t$?

Accepted Answer

Correct Option: A. Solution: According to Joule's law of heating, the heat produced in a resistor is given by $H = I^2 R t$, where $I$ is the current, $R$ is the resistance, and $t$ is the time.

Question 12

If a net charge $Q$ flows across any cross-section of a conductor in time $t$, what is the expression for the current $I$ through the cross-section?

Accepted Answer

Correct Option: A. Solution: The current $I$ through a cross-section is defined as the amount of charge $Q$ flowing through it per unit time $t$, hence $I = Q/t$.

Question 13

In a parallel circuit, a 10 Ω resistor, a 20 Ω resistor, and a 30 Ω resistor are connected across a 12 V battery. What is the total current supplied by the battery?

Accepted Answer

Correct Option: C. Solution: The total current is the sum of currents through each resistor. $I_1 = \frac{12\, V}{10\, \Omega} = 1.2\, A$, $I_2 = \frac{12\, V}{20\, \Omega} = 0.6\, A$, $I_3 = \frac{12\, V}{30\, \Omega} = 0.4\, A$. Total current $I = I_1 + I_2 + I_3 = 1.2\, A + 0.6\, A + 0.4\, A = 2.2\, A$.

Question 14

What is the total current flowing through a parallel circuit with resistors $R_1 = 5 \ \Omega$, $R_2 = 10 \ \Omega$, and $R_3 = 30 \ \Omega$ connected to a 12 V battery?

Accepted Answer

Correct Option: D. Solution: In a parallel circuit, the total current is the sum of the currents through each resistor. Using Ohm's law, $I_1 = \frac{12 V}{5 \ \Omega} = 2.4 A$, $I_2 = \frac{12 V}{10 \ \Omega} = 1.2 A$, $I_3 = \frac{12 V}{30 \ \Omega} = 0.4 A$. Thus, $I_{total} = I_1 + I_2 + I_3 = 2.4 A + 1.2 A + 0.4 A = 4 A$.

Question 15

A wire of resistance 10 Ω is doubled in length. What is the new resistance of the wire assuming uniform cross-sectional area and material?

Accepted Answer

Correct Option: B. Solution: Resistance is directly proportional to the length of the wire. Doubling the length doubles the resistance: $R_{new} = 2 	imes 10 \Omega = 20 \Omega$.

Question 16

Which of the following is true about resistors connected in parallel?

Accepted Answer

Correct Option: C. Solution: In a parallel circuit, the reciprocal of the total resistance is the sum of the reciprocals of the individual resistances, making the total resistance less than any individual resistance.

Question 17

A copper wire has a diameter of 0.5 mm and a resistivity of $1.6 	imes 10^{-8} \, \Omega \, 	ext{m}$. What will be the length of this wire to make its resistance $10 \, \Omega$? How much does the resistance change if the diameter is doubled?

Accepted Answer

Correct Option: C. Solution: Using the formula $R = ho \frac{l}{A}$, where $A = \pi \left(\frac{d}{2}ight)^2$, we find the length $l = \frac{R \cdot A}{ho}$. Substituting $R = 10 \, \Omega$, $ho = 1.6 	imes 10^{-8} \, \Omega \, 	ext{m}$, and $d = 0.5 	imes 10^{-3} \, 	ext{m}$, we calculate $l = 98.5 \, 	ext{m}$. Doubling the diameter quadruples the area, reducing the resistance by a factor of 4, so it becomes $2.5 \, \Omega$.

Question 18

If a resistor with a resistance of $10 \Omega$ is connected to a $5$ V battery, what is the current flowing through the resistor?

Accepted Answer

Correct Option: B. Solution: Using Ohm's Law $I = \frac{V}{R}$, the current $I = \frac{5 V}{10 \Omega} = 0.5 A$.

Question 19

Three resistors of resistances 2 Ω, 3 Ω, and 6 Ω are connected in parallel. What is the equivalent resistance of the combination?

Accepted Answer

Correct Option: A. Solution: The equivalent resistance $R_p$ for parallel resistors is given by $\frac{1}{R_p} = \frac{1}{2} + \frac{1}{3} + \frac{1}{6} = 1$. Thus, $R_p = 1 \Omega$.

Question 20

What is the equivalent resistance of three resistors with resistances $R_1 = 5 \, \Omega$, $R_2 = 10 \, \Omega$, and $R_3 = 30 \, \Omega$ when connected in parallel?

Accepted Answer

Correct Option: A. Solution: The reciprocal of the equivalent resistance $R_p$ is the sum of the reciprocals of the individual resistances: $$\frac{1}{R_p} = \frac{1}{5} + \frac{1}{10} + \frac{1}{30} = \frac{1}{3}$$, so $R_p = 3 \, \Omega$.

Question 21

If a 12 V battery is connected across an unknown resistor and a current of 2.5 mA flows through the circuit, what is the resistance of the resistor?

Accepted Answer

Correct Option: A. Solution: Using Ohm's law $V = IR$, we find $R = \frac{V}{I}$. Substituting $V = 12 \, V$ and $I = 2.5 	imes 10^{-3} \, A$, we calculate $R = \frac{12}{2.5 	imes 10^{-3}} = 4800 \, \Omega = 4.8 \, k\Omega$.

Question 22

Which of the following expressions correctly represents electric power in a circuit?

Accepted Answer

Correct Option: D. Solution: Electric power can be expressed as $P = VI$, $P = I^2R$, or $P = \frac{V^2}{R}$ depending on the known variables.

Question 23

An electric heater of resistance $44\ \Omega$ draws $5\ A$ from the service mains for $2$ hours. Calculate the heat generated in the heater.

Accepted Answer

Correct Option: C. Solution: Using Joule's Law of Heating, $H = I^2Rt$, where $I = 5\ A$, $R = 44\ \Omega$, and $t = 2\ 	ext{hours} = 7200\ 	ext{seconds}$. Thus, $H = (5)^2 	imes 44 	imes 7200 = 1584000\ J$.

Question 24

If a charge of 3 coulombs is moved across two points having a potential difference of 9 volts, how much work is done?

Accepted Answer

Correct Option: C. Solution: The work done is calculated using the formula $W = VQ$. Substituting the given values, $W = 9 	imes 3 = 27$ joules.

Question 25

Which instrument is used to measure the potential difference across two points in an electric circuit?

Accepted Answer

Correct Option: B. Solution: A voltmeter is used to measure the potential difference across two points in an electric circuit. It is connected in parallel across the points.

Question 26

In a series circuit with resistors $R_1 = 20 \, \Omega$ and $R_2 = 4 \, \Omega$, connected to a $6 \, V$ battery, what is the total resistance of the circuit?

Accepted Answer

Correct Option: A. Solution: In a series circuit, the total resistance is the sum of individual resistances: $R = R_1 + R_2 = 20 \, \Omega + 4 \, \Omega = 24 \, \Omega$.

Question 27

What happens to the resistance of a wire if its length is doubled and its cross-sectional area is halved?

Accepted Answer

Correct Option: C. Solution: Resistance $R$ is directly proportional to the length $l$ and inversely proportional to the cross-sectional area $A$. Doubling the length and halving the area will quadruple the resistance.

Question 28

A 100 W electric bulb and a 60 W electric bulb are connected in parallel to a 220 V supply. What is the total current drawn from the supply?

Accepted Answer

Correct Option: C. Solution: The power of each bulb is given by $P = VI$. For the 100 W bulb, $I_1 = \frac{100 W}{220 V} = 0.45 A$. For the 60 W bulb, $I_2 = \frac{60 W}{220 V} = 0.27 A$. Total current $I = I_1 + I_2 = 0.45 A + 0.27 A = 0.72 A$.

Question 29

According to Joule's Law of Heating, which of the following factors does NOT affect the heat produced in a resistor?

Accepted Answer

Correct Option: D. Solution: Joule's Law of Heating states that the heat produced in a resistor is directly proportional to the square of the current, the resistance, and the time. Voltage is not directly mentioned in the formula $H = I^2Rt$.

Question 30

Which of the following statements about Ohm's Law is incorrect?

Accepted Answer

Correct Option: A. Solution: Ohm's Law is not applicable to all materials; it is valid only for ohmic materials where the temperature remains constant.

Question 31

A 400 W electric refrigerator operates for 8 hours a day. What is the total energy consumed in 30 days?

Accepted Answer

Correct Option: A. Solution: The total energy consumed is $400 	ext{ W} 	imes 8 	ext{ hours/day} 	imes 30 	ext{ days} = 96000 	ext{ Wh} = 96 	ext{ kWh}$.

Question 32

A 220 V electric iron has a resistance of 50 Ω. Calculate the current flowing through the iron and the heat produced in 10 minutes.

Accepted Answer

Correct Option: A. Solution: The current $I$ is given by $I = \frac{V}{R} = \frac{220}{50} = 4.4 	ext{ A}$. The heat produced $H = I^2 R t = (4.4)^2 	imes 50 	imes 600 = 580,800 	ext{ J}$.

Question 33

What is the SI unit of electric potential difference?

Accepted Answer

Correct Option: B. Solution: The SI unit of electric potential difference is volt (V), named after Alessandro Volta.

Question 34

A circuit consists of a 6 V battery connected in series with a 2 Ω resistor and a 4 Ω resistor. What is the total current flowing through the circuit?

Accepted Answer

Correct Option: B. Solution: The total resistance in the circuit is $R = 2 Ω + 4 Ω = 6 Ω$. Using Ohm's law, $I = V/R = 6 V / 6 Ω = 1 A$. Therefore, the current flowing through the circuit is 1 A.

Question 35

A copper wire has a diameter of 0.5 mm and a resistivity of $1.6 	imes 10^{-8} \ \Omega \ m$. What will be the length of this wire to make its resistance 10 $\Omega$?

Accepted Answer

Correct Option: B. Solution: Using the formula $R = \rho \frac{l}{A}$, where $A = \pi (d/2)^2$, we can solve for $l$ to find the length.

Question 36

In a circuit with three resistors of 5 Ω, 10 Ω, and 15 Ω connected in parallel, what is the equivalent resistance?

Accepted Answer

Correct Option: A. Solution: For parallel resistors, the reciprocal of the equivalent resistance is the sum of the reciprocals of individual resistances: $\frac{1}{R_{eq}} = \frac{1}{5} + \frac{1}{10} + \frac{1}{15} = \frac{11}{30}$. Thus, $R_{eq} = \frac{30}{11} \approx 2.73 \Omega$.

Question 37

A 100 W electric bulb is connected to a 220 V supply. What is the resistance of the bulb?

Accepted Answer

Correct Option: A. Solution: The power $P = 100\ W$ and the voltage $V = 220\ V$. Using the formula $P = V^2/R$, we can solve for $R$: $R = V^2/P = (220)^2/100 = 484\ \Omega$.

Question 38

In an electric circuit, what is the direction of conventional current flow?

Accepted Answer

Correct Option: A. Solution: Conventionally, the direction of electric current is taken as opposite to the direction of flow of electrons, which are negative charges. Thus, it flows from the positive to the negative terminal.

Question 39

Consider a circuit with a battery of 12 V connected to three resistors in series with resistances of 2 Ω, 3 Ω, and 5 Ω. What is the total current flowing through the circuit?

Accepted Answer

Correct Option: B. Solution: The total resistance in series is $R = 2\, \Omega + 3\, \Omega + 5\, \Omega = 10\, \Omega$. Using Ohm's law, $I = \frac{V}{R} = \frac{12\, V}{10\, \Omega} = 1\, A$.

Question 40

An electric iron connected to a 220 V supply has a resistance of 44 Ω. How much power is consumed by the iron?

Accepted Answer

Correct Option: B. Solution: The power consumed $P$ is given by $P = \frac{V^2}{R} = \frac{(220 	ext{ V})^2}{44 \Omega} = 1100 	ext{ W}$.

Question 41

Which of the following terms does not represent electrical power in a circuit?

Accepted Answer

Correct Option: B. Solution: Electrical power can be represented by $P = VI$, $P = I^2 R$, and $P = \frac{V^2}{R}$. The term $IR^2$ does not represent electrical power.

Question 42

An electric iron is rated at 1000 W when operated at 220 V. If a 5 A fuse is used in the circuit, will the fuse blow when the iron is used?

Accepted Answer

Correct Option: B. Solution: The current drawn by the electric iron is $\frac{1000 	ext{ W}}{220 	ext{ V}} \approx 4.54 	ext{ A}$, which is within the 5 A fuse rating.

Question 43

According to Ohm's Law, what is the relationship between voltage ($V$), current ($I$), and resistance ($R$) in a conductor?

Accepted Answer

Correct Option: A. Solution: Ohm's Law states that the voltage across a conductor is directly proportional to the current flowing through it, with the resistance being the proportionality constant, expressed as $V = IR$.

Question 44

If a 60 W bulb and a 100 W bulb are connected in parallel to a 220 V supply, what is the total power consumed?

Accepted Answer

Correct Option: A. Solution: In a parallel circuit, the total power is the sum of the individual powers. Thus, $P_{total} = 60 W + 100 W = 160 W$.

Question 45

Three resistors with resistances $R_1 = 2 \ \Omega$, $R_2 = 3 \ \Omega$, and $R_3 = 6 \ \Omega$ are connected in series. What is the total equivalent resistance of the circuit?

Accepted Answer

Correct Option: A. Solution: In a series circuit, the total resistance is the sum of individual resistances: $R_{total} = R_1 + R_2 + R_3 = 2 \ \Omega + 3 \ \Omega + 6 \ \Omega = 11 \ \Omega$.

Question 46

A potential difference of 15 V is applied across a resistor, resulting in a current of 3 A. What is the resistance of the resistor?

Accepted Answer

Correct Option: B. Solution: Using Ohm's law, $R = \frac{V}{I} = \frac{15\, V}{3\, A} = 5\, \Omega$.

Question 47

An electric iron of resistance $20 \ \Omega$ is connected to a 220 V supply. Calculate the heat produced in 30 seconds.

Accepted Answer

Correct Option: A. Solution: Using the formula $H = I^2 Rt$ and Ohm's law $I = \frac{V}{R}$, we find $I = \frac{220 V}{20 \ \Omega} = 11 A$. Then $H = (11 A)^2 	imes 20 \ \Omega 	imes 30 s = 7260 J$.

Question 48

The SI unit of electric power is kilowatt (kW).

Accepted Answer

Answer: False. Solution: The SI unit of electric power is watt (W), not kilowatt. Kilowatt is a larger unit used in practical applications.

Question 49

The resistance of a conductor is directly proportional to its length and inversely proportional to its cross-sectional area.

Accepted Answer

Answer: True. Solution: The resistance $R$ of a conductor is given by $R = \rho \frac{l}{A}$, where $l$ is the length and $A$ is the cross-sectional area. This shows that resistance is directly proportional to length and inversely proportional to cross-sectional area.

Question 50

In a parallel circuit, the total current flowing through the circuit is the sum of the currents through each resistor.

Accepted Answer

Answer: True. Solution: In a parallel circuit, the total current is the sum of the currents through each branch, as the current divides among the parallel paths.

Question 51

The resistance of a conductor is directly proportional to its length and inversely proportional to its cross-sectional area.

Accepted Answer

Answer: True. Solution: According to the formula $R = \rho \frac{l}{A}$, the resistance $R$ is directly proportional to the length $l$ and inversely proportional to the cross-sectional area $A$.

Question 52

The power consumed by a device can be expressed as $P = V^2/R$.

Accepted Answer

Answer: True. Solution: The power consumed in an electric circuit can be expressed using the formula $P = V^2/R$, which is derived from Ohm's law and the definition of power.

Question 53

The potential difference across a conductor is measured using an ammeter.

Accepted Answer

Answer: False. Solution: The potential difference across a conductor is measured using a voltmeter, not an ammeter.

Question 54

In a series circuit, the equivalent resistance is always greater than the largest individual resistance.

Accepted Answer

Answer: True. Solution: When resistors are connected in series, the total resistance is the sum of all individual resistances, which makes the equivalent resistance greater than any single resistor in the series.

Question 55

Joule's Law of Heating implies that the heat produced in a resistor is inversely proportional to the resistance for a given current.

Accepted Answer

Answer: False. Solution: Joule's Law of Heating implies that the heat produced is directly proportional to the resistance for a given current, not inversely.

Question 56

When resistors are connected in series, the total resistance of the combination is less than the smallest individual resistance.

Accepted Answer

Answer: False. Solution: When several resistors are joined in series, the resistance of the combination equals the sum of their individual resistances, which is greater than any individual resistance.

Question 57

In an electric circuit, the direction of electric current is conventionally considered to be the same as the direction of electron flow.

Accepted Answer

Answer: False. Solution: Conventionally, the direction of electric current is taken as opposite to the direction of the flow of electrons, which are negative charges.

Question 58

Ohm's Law states that the potential difference across a conductor is directly proportional to the current flowing through it, provided the temperature remains constant.

Accepted Answer

Answer: True. Solution: According to Ohm's Law, the relationship between voltage ($V$), current ($I$), and resistance ($R$) is given by $V = IR$. This implies that for a constant temperature, the potential difference across a conductor is directly proportional to the current flowing through it.

Question 59

In a metallic conductor, electric current is the flow of positive charges.

Accepted Answer

Answer: False. Solution: In metallic conductors, electric current is constituted by the flow of electrons, which are negative charges. Conventionally, the direction of electric current is taken as opposite to the direction of electron flow.

Question 60

The heating effect of electric current is utilized in devices like electric heaters and electric bulbs.

Accepted Answer

Answer: True. Solution: The heating effect of electric current is indeed used in devices such as electric heaters, electric irons, and electric bulbs, where the heat generated by the current is a desired effect.

Question 61

Ohm's Law states that the potential difference across a conductor is directly proportional to the current flowing through it, provided the temperature remains constant.

Accepted Answer

Answer: True. Solution: Ohm's Law is defined as $V = IR$, where $V$ is the potential difference, $I$ is the current, and $R$ is the resistance. This relationship holds true as long as the temperature remains constant.

Question 62

The formula for electric power can be expressed as $P = I^2R$.

Accepted Answer

Answer: True. Solution: Electric power can indeed be expressed as $P = I^2R$, which is derived from the basic power formula $P = VI$ by substituting $V = IR$ from Ohm's law.

Question 63

The heating effect of electric current is utilized in devices such as electric heaters and fuses.

Accepted Answer

Answer: True. Solution: The heating effect of electric current is indeed used in devices like electric heaters, where the current is converted into heat energy to perform work such as heating. Fuses also use this effect to protect circuits by melting when the current is too high.

Question 64

According to Joule's Law of Heating, the heat produced in a resistor is directly proportional to the square of the current flowing through it.

Accepted Answer

Answer: True. Solution: Joule's Law of Heating states that the heat produced in a resistor is directly proportional to the square of the current, the resistance, and the time the current flows through the resistor.

Electricity

Learning Objectives

Learning Objectives

Revision Notes & Summary

Chapter Notes

Electric Current and Circuit

Ohm's Law

Electric Potential and Potential Difference

Resistance and Resistivity

Series and Parallel Circuits

Joule's Law of Heating

Electric Power

Applications of Heating Effect

Example Problems

Summary

Exam Tips & Common Mistakes

Common Mistakes & Exam Tips

Electric Current and Circuit

Ohm's Law

Electric Potential and Potential Difference

Resistance and Resistivity

Series and Parallel Circuits

Joule's Law of Heating

Electric Power

Applications of Heating Effect

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Multiple Choice Questions

Q1.An electric bulb is connected to a 220 V generator and draws a current of 0.50 A. What is the power of the bulb?

Correct Answer: A

Q2.A circuit consists of a 6 V battery connected in series with a 2 Ω resistor and a 4 Ω resistor. What is the total current flowing through the circuit?

Correct Answer: D

Q3.An electric heater rated at 1000 W is used for 30 minutes. How much heat energy is produced by the heater?

Correct Answer: B

Q4.Which of the following factors does NOT affect the resistance of a conductor?

Correct Answer: D

Q5.A circuit consists of a 10 Ω resistor connected in series with a 5 Ω resistor and a battery of 15 V. What is the current flowing through the circuit?

Correct Answer: A

Q6.An electric heater of resistance 44 Ω44 \, \Omega44Ω draws 5 A5 \, A5A from the service mains for 222 hours. Calculate the rate at which heat is developed in the heater.

Correct Answer: B

Q7.If a 12 V battery is connected in series with resistors of 0.2 Ω0.2 \, \Omega0.2Ω, 0.3 Ω0.3 \, \Omega0.3Ω, 0.4 Ω0.4 \, \Omega0.4Ω, 0.5 Ω0.5 \, \Omega0.5Ω, and 12 Ω12 \, \Omega12Ω, what is the current through the 12 Ω12 \, \Omega12Ω resistor?

Correct Answer: A

Q8.A circuit consists of a 12Ω12 \Omega12Ω resistor connected to a 242424 V battery. If the resistance is doubled, what happens to the current in the circuit?

Correct Answer: C

Q9.Which of the following devices utilizes the heating effect of electric current for its operation?

Correct Answer: A

Q10.Two lamps, one rated 100 W100 \, W100W at 220 V220 \, V220V, and the other 60 W60 \, W60W at 220 V220 \, V220V, are connected in parallel to an electric mains supply. What current is drawn from the line if the supply voltage is 220 V220 \, V220V?

Correct Answer: B

Q11.A resistor with resistance RRR is connected to a voltage source of VVV volts. If the current flowing through the resistor is III amperes, according to Joule's law of heating, what is the heat produced in the resistor in time ttt?

Correct Answer: A

Q12.If a net charge QQQ flows across any cross-section of a conductor in time ttt, what is the expression for the current III through the cross-section?

Correct Answer: A

Q13.In a parallel circuit, a 10 Ω resistor, a 20 Ω resistor, and a 30 Ω resistor are connected across a 12 V battery. What is the total current supplied by the battery?

Correct Answer: C

Q14.What is the total current flowing through a parallel circuit with resistors R1=5 ΩR_1 = 5 \ \OmegaR1​=5 Ω, R2=10 ΩR_2 = 10 \ \OmegaR2​=10 Ω, and R3=30 ΩR_3 = 30 \ \OmegaR3​=30 Ω connected to a 12 V battery?

Correct Answer: D

Q15.A wire of resistance 10 Ω is doubled in length. What is the new resistance of the wire assuming uniform cross-sectional area and material?

Correct Answer: B

Q16.Which of the following is true about resistors connected in parallel?

Correct Answer: C

Q17.A copper wire has a diameter of 0.5 mm and a resistivity of 1.6×10−8 Ω m1.6 \times 10^{-8} \, \Omega \, \text{m}1.6×10−8Ωm. What will be the length of this wire to make its resistance 10 Ω10 \, \Omega10Ω? How much does the resistance change if the diameter is doubled?

Correct Answer: C

Q18.If a resistor with a resistance of 10Ω10 \Omega10Ω is connected to a 555 V battery, what is the current flowing through the resistor?

Correct Answer: B

Q19.Three resistors of resistances 2 Ω, 3 Ω, and 6 Ω are connected in parallel. What is the equivalent resistance of the combination?

Correct Answer: A

Q20.What is the equivalent resistance of three resistors with resistances R1=5 ΩR_1 = 5 \, \OmegaR1​=5Ω, R2=10 ΩR_2 = 10 \, \OmegaR2​=10Ω, and R3=30 ΩR_3 = 30 \, \OmegaR3​=30Ω when connected in parallel?

Correct Answer: A

Q21.If a 12 V battery is connected across an unknown resistor and a current of 2.5 mA flows through the circuit, what is the resistance of the resistor?

Correct Answer: A

Q22.Which of the following expressions correctly represents electric power in a circuit?

Correct Answer: D

Q23.An electric heater of resistance 44 Ω44\ \Omega44 Ω draws 5 A5\ A5 A from the service mains for 222 hours. Calculate the heat generated in the heater.

Correct Answer: C

Q24.If a charge of 3 coulombs is moved across two points having a potential difference of 9 volts, how much work is done?