NEET Physics Heating Effect of Electric Current MCQs Set A

Question: A battery of emf 10V and internal resistance 30hm is conncted to a resister. The current in the circuit is 0.5 amp. The terminal voltage of the battery when the circuit is closed is
a) 8.5V
b) 1.5V
c) zero
d) 10V
Answer: 8.5V

Question:  The cause of heat production in a current carrying conductor is
a) collisions of free electrons with atoms or ions of the conductor
b) high resistance value
c) high drift speed of free electrons
d) collisions of free electrons with one another
Answer:  collisions of free electrons with atoms or ions of the conductor

Question: Resistance of conductor is doubled keeping the potential difference across it constant. The rate of generation of heat will
a) be halved
b) become four times
c) become one fourth
d) be doubled
Answer: be halved

Question: The resistance of hot tungsten filament is about 10 times the cold resistance. What will be the resistance of 100 W and 200 V lamp when not in use ?
a)

b)

c)

d) None of these

Answer: 

Question:  A 25 W and 100 W bulb are joined in series and connected to the mains. Which bulb will glow brighter?
a) 25 W bulb
b) 100 W bulb
c) Both bulb will glow brighter
d) None will glow brighter
Answer:  25 W bulb

Question: An electric fan and a heater are marked as 100 W, 220 V and 1000 W, 220 V respectively. The resistance of heater is
a) lesser than that of fan
b) greater than that of fan
c) zero
d) equal to that of fan
Answer: lesser than that of fan

Question: Water boils in the electric kettle in 15 minutes after switching on. If the length of heating wire is decreased to 2/3 of its initial value, then the same amount of water will boil with the same supply voltage in
a) 10 minutes
b) 15 minutes
c) 8 minutes
d) 12 minutes
Answer: 10 minutes

Question:  A wire of radius r and another wire of radius 2r, both of same material and length are connected in series to each other. The combination is connected across a battery. The ratio of the heats produced in the two wires will be
a) 4.00
b) 2.00
c) 0.50
d) 0.25
Answer:  4.00

Question:

a)

b)

c)

d)

Answer:

Question:

a)

b)

c)

d)

Answer:

Question:  It takes 12 minutes to boil 1 litre of water in an electric kettle. Due to some defect it becomes necessary to remove 20% turns of heating coil of the kettle. After repair, how much time will it take to boil 1 litre of water ?
a) 9.6 minute
b) 18.2 minute
c) 16.8 minute
d) 14.4 minute
Answer: 9.6 minute

Question:  In household electric circuit
I. all electric appliances drawing power are joined in parallel.
II. a switch may be either in series or in parallel with the appliance which it controls.
III. if a switch is in parallel with an appliance, it will draw power when the switch is in the ‘off’ position (open).
IV. if a switch is in parallel with an appliance, the fuse will blow (burn out) when the switch is put ‘on’ closed.
Which of the above statements are correct?
a) I, III and IV
b) I, II and IV
c) II, III and IV
d) I and IV
Answer:  I, III and IV

More Questions..........................................................

Question: A torch bulb rated as 4.5 W, 1.5 V is connected as shown in fig. The e.m.f. of the cell, needed to make the bulb glow at full intensity is

a) 13.5 V
b) 2.67 V
c) 1.5 V
d) 4.5 V
Answer: 13.5 V

Question: Forty electric bulbs are connected in series across a 220 V supply. After one bulb is fused the remaining 39 are connected again in series across the same supply. The illumination will be
a) more with 39 bulbs than with 40
b) equal in both the cases
c) more with 40 bulbs than with 39
d) None of these
Answer:  more with 39 bulbs than with 40

Question:

a) Current in the circuit is maximum when R = r
b) Current in the circuit is maximum when R >> r
c) Power delivered to resistor is maximum when R = 2r
d) Potential difference across the terminals of the battery is maximum when R = r
Answer: Current in the circuit is maximum when R = r

Question: You have the following appliances each of 500 watt running on 220 volts a.c. (1) electric iron (2) an electric lamp (3) an electric room heater. The electric resistance is
a) same in all the three cases
b) maximum for the electric iron
c) maximum for the electric lamp
d) maximum for the heater
Answer: same in all the three cases

Question:

a) 2 : 1
b) 5 : 2
c) 1 : 2
d) 4 : 3
Answer: 2 : 1

Question:  A 100 watt bulb working on 200 volt has resistance R and a 200 watt bulb working on 100 volt has resistance S then R/S is
a) 8
b) 4
c) 6
d) 2
Answer: 8

Question: A potentiometer consists of a wire of length 4m and resistance 10W. It is connected to a cell of e.m.f. 3V. The potential gradient of wire is
a) 5V/m
b) 2V/m
c) 5V/m
d) 10V/m
Answer: 5V/m

Question:

a) the galvanometer shows no change in deflection whether S is open or closed
b) the galvanometer shows no deflection
c) the galvanometer show a deflection when switch S is open
d) the galvanometer shows a deflection when switch S is closed
Answer: the galvanometer shows no change in deflection whether S is open or closed