#### Practice Questions on Heating Effect of Current:

**Ques:** A 60 *watt* bulb carries a current of 0.5 *amp*. The total chaNNrge passing through it in 1 *hour* is

(a) 3600 *coulomb
*(b) 3000

*coulomb*

(c) 2400

*coulomb*

(d) 1800

*coulomb*

Related: Questions on Electrochemistry

**Ques:** A constant voltage is applied between the two ends of a metallic wire. If both the length and the radius of the wire are doubled, the rate of heat developed in the wire

(a) Will be doubled

(b) Will be halved

(c) Will remain the same

(d) Will be quadrupled

**Ques:** Which of the following is not a correct statement

(a) Resistivity of electrolytes decreases on increasing temperature

(b) Resistance of mercury falls on decreasing its temperature

(c) When joined in series a 40 *W* bulb glows more than a 60 *W* bulb

(d) Resistance of 40 *W *bulb is less than the resistance of 60 *W* bulb

**Ques:** How much energy in kilowatt hour is consumed in operating ten 50 watt bulbs for 10 hours per day in a month (30 days).

(a) 1500

(b) 5,000

(c) 15

(d) 150

**Ques:** If 2.2 *kilowatt* power is transmitted through a 10 *ohm* line at 22000 *volt*, the power loss in the form of heat will be

(a) 0.1 *watt
*(b) 1

*watt*

(c) 10

*watt*

(d) 100

*watt*

**Ques:** In the above question, the power lost in the cable during transmission is

(a) 12.5 *kW
*(b) 6.25

*kW*

(c) 25

*kW*

(d) 3.15

*kW*

Related: Diversity of Living Organism Questions / Answers

**Ques:** You are given three bulbs of 25, 40 and 60 *watt*. Which of them has lowest resistance

(a) 25 *watt* bulb

(b) 40 *watt* bulb

(c) 60 *watt* bulb

(d) Information is insufficient

**Ques:** If a 30 *V*, 90 *W* bulb is to be worked on a 120 *V* line, a resistance of how many ohms should be connected in series with the bulb

(a) 10 *ohm*

(b) 20 *ohm
*(c) 30

*ohm*

(d) 40

*ohm*

**Ques:** 4 bulbs marked 40 *W*, 250 *V* are connected in series with 250 *V* mains. The total power is

(a) 10 *W
*(b) 40

*W*

(c) 320

*W*

(d) 160

*W*

**Ques:** An electric fan and a heater are marked as 100 *watt*, 220 *volt* and 1000 *watt*, 220 volt respectively. The resistance of the heater is

(a) Zero

(b) Greater than that of the fan

(c) Less than that of the fan

(d) Equal to that of the fan

Related: current electricity (Physics)

**Ques:** A heater draws a current of 2*A* when connected to a 250*V* source. The rate of energy dissipation is

(a) 500* W*

(b) 1000* W
*(c) 250

*W*

(d) 125

*W*

**Ques:** Three bulbs of 40*W*, 60*W* and 100*W* are arranged in series with 220*V*. Which bulb has minimum resistance

(a) 40*W*

(b) 60*W
*(c) 100

*W*

(d) Equal in all bulbs

**Ques:** Three electric bulbs of rating 60*W* each are joined in series and then connected to electric mains. The power consumed by these three bulbs will be

(a) 180 *W*

(b) 60 *W
*(c) 20

*W*

(d) 20/3 W

**Ques:** The amount of heat produced in a resistor when a current is passed through it can be found using

(a) Faraday’s Law

(b) Kirchhoff’s Law

(c) Laplace’s Law

(d) Joule’s Law

**Ques:** Two bulbs, one of 50 *watt* and another of 25 *watt* are connected in series to the mains. The ratio of the currents through them is

(a) 2 : 1

(b) 1 : 2

(c) 1 : 1

(d) Without voltage, cannot be calculated

**Ques:** A 10 *ohm* electric heater operates on a 110 *V* line. Calculate the rate at which it develops heat in watts

(a) 1310 *W
*(b) 670

*W*

(c) 810

*W*

(d) 1210

*W*

**Ques:** Two bulbs of 100 *W* and 200 *W* working at 220 *volt* are joined in series with 220 *volt* supply. Total power consumed will be approximately.

(a) 65 *watt*

(b) 33 *watt
*(c) 300

*watt*

(d) 100

*watt*

**Ques:** Electric room radiator which operates at 225 *volts* has resistance of 50 *ohms*. Power of the radiator is approximately

(a) 100 *W
*(b) 450

*W*

(c) 750

*W*

(d) 1000

*W*

**Ques:** Two electric lamps of 40 watt each are connected in parallel. The power consumed by the combination will be

(a) 20 *watt
*(b) 60

*watt*

(c) 80

*watt*

(d) 100

*watt*

**Ques:** If two electric bulbs have 40 *W* and 60 *W* rating at 220 *V*, then the ratio of their resistances will be

(a) 9 : 4

(b) 4 : 3

(c) 3 : 8

(d) 3 : 2

Related: Ray optics questions

**Ques:** Two wires with resistances *R* and 2*R* are connected in parallel, the ratio of heat generated in 2*R* and *R* is

(a) 1 : 2

(b) 2 : 1

(c) 1 : 4

(d) 4 : 1

**Ques:** An electric heater kept in vacuum is heated continuously by passing electric current. Its temperature

(a) Will go on rising with time

(b) Will stop after sometime as it will loose heat to the surroundings by conduction

(c) Will rise for sometime and there after will start falling

(d) Will become constant after sometime because of loss of heat due to radiation

**Ques:** If two bulbs of wattage 25 and 30, each rated at 220 *volts*, are connected in series with a 440 *volt* supply, which bulb will fuse

(a) 25 *W* bulb

(b) 30 *W* bulb

(c) Neither of them

(d) Both of them

**Ques:** What is immaterial for an electric fuse wire

(a) Specific resistance of the wire

(b) Radius of the wire

(c) Length of the wire

(d) Current flowing through the wire

**Ques:** Some electric bulbs are connected in series across a 220 *V* supply in a room. If one bulb is fused then remaining bulbs are connected again in series across the same supply. The illumination in the room will

(a) Increase

(b) Decrease

(c) Remains the same

(d) Not continuous

**Ques:** The heat produced by a 100 *watt* heater in 2 minute will be equal to

(a) 12 x 10^{3} J

(b) 10 x 10^{3} J

(c) 6 x 10^{3} J

(d) 3 x 10^{3} J

**Ques:** A 25 *watt*, 220 *volt* bulb and a 100 *watt*, 220 *volt* bulb are connected in parallel across a 220 *volt* line. Which bulb will glow more brightly

(a) 25 *watt* bulb

(b) 100 *watt* bulb

(c) Both will have same brightness

(d) First 25 *watt* then 100 *watt*

Related: d and f block elements reasoning questions

**Ques:** The electric current passing through a metallic wire produces heat because of

(a) Collisions of conduction electrons with each other

(b) Collisions of the atoms of the metal with each other

(c) The energy released in the ionization of the atoms of the metal

(d) Collisions of the conduction electrons with the atoms of the metallic wires

**Ques:** A heater coil connected to a supply of a 220 *V* is dissipating some power P_{1}. The coil is cut into half and the two halves are connected in parallel. The heater now dissipates a power P_{2}. The ratio of power P_{1} : P_{2} is

(a) 2 : 1

(b) 1 : 2

(c) 1 : 4

(d) 4 : 1

**Ques:** 3 identical bulbs are connected in series and these together dissipate a power *P*. If now the bulbs are connected in parallel, then the power dissipated will be

(a) P/3

(b) 3*P
*(c) 9

*P*

(d) P/9

**Ques:** A wire when connected to 220*V *mains supply has power dissipation P_{1}. Now the wire is cut into two equal pieces which are connected in parallel to the same supply. Power dissipation in this case is P_{2}. Then P_{2} : P_{1} is

(a) 1

(b) 4

(c) 2

(d) 3

**Ques:** A heater coil is cut into two equal parts and only one part is now used in the heater. The heat generated will now be

(a) One fourth

(b) Halved

(c) Doubled

(d) Four times

**Ques:** Two electric bulbs *A* and *B* are rated as 60 *W* and 100 *W*. They are connected in parallel to the same source. Then,

(a) Both draw the same current

(b) *A* draws more current than *B
*(c)

*B*draws more current than

*A*

(d) Current drawn are in the ratio of their resistances

**Ques:** An electric iron draws 5 *amp*, a TV set draws 3 *amp* and refrigerator draws 2 *amp* from a 220 *volt* main line. The three appliances are connected in parallel. If all the three are operating at the same time, the fuse used may be of

(a) 20 *amp*

(b) 5 *amp*

(c) 15 *amp*

(d) 10 *amp*