Q.1.
The power of heater is 750W at 1000°C. What will be its power at 200°C if α=4 ×10-4C
-
29%
a) 500 W
-
29%
b) 990 W
-
29%
c)250 W
-
12%
d)1500 W
Q.2.
Two electric bulbs, one of 200 volt - 60 watt and the other of 200 volt - 200 watt are connected in a house wiring circuits
-
27%
a)they have equal currents through them
-
18%
b) the resistance of the filaments in both the bulbs is same
-
55%
c)the resistance of the filament in 60 watt bulb is more than the resistance in 200 watt bulb
-
0%
d)the resistance of the filament in 200 watt bulb is more than the resistance in 60 watt bulb
Q.3.
The electric bulbs have tungsten filaments of same length. If one of them gives 60 watts and the other 100 watts then
-
20%
a) 100 watts bulbs has thicker filament
-
20%
b) 60 watts bulb has thicker filament
-
40%
c)both filaments are of same thickness
-
20%
d)it is possible to get different wattage unless the lengths are different
Q.4.
Find the power wasted in the transmission cable of resistance 0.05Ω when 10 kW is transmitted at 200 volts
-
18%
a) 0.0125 kW
-
55%
b) 0.125 kW
-
18%
c)25 kW
-
9%
d)37.5 kW
Q.5.
A current of 0.5 amp flows in a 60 W lamp, then the total charge passing through it in one hour will be
-
36%
a) 1800 coulombs
-
9%
b) 2400 coulombs
-
45%
c) 3000 coulombs
-
9%
d) 36000 coulombs
Q.6.
A resistance coil of 60Ω is immersed in 42 kg of water. A current of 7A is passed through it. The rise in temperature of water per minutes is
-
22%
a)4°C
-
22%
b) 8°C
-
56%
c)1°C
-
0%
d)12°C
Q.7.
It is well known that resistance of the filament of bulb charges with temperature. If an electric bulb rated 220 volt, 100 watt is connected to a source of voltage 220(0.5) volt then the actual power will be
-
0%
a) 100(0.8) watt
-
25%
b) (100) ( 0.8)2 watt
-
75%
c)more than 100(0.8) watt but less than 100 watt
-
0%
d)more than 100(0.8) 2 watt but less than 100(0.8) watt
Q.8.
A wire when connected to 220V means supply has power dissipation PNow the wire is cut into two equal pieces which are connected in parallel to the same supply. Power dissipation in this case is PThen P2 : P1 is [ AIEEE 2002]
-
0%
a)1
-
50%
b) 4
-
50%
c)2
-
0%
d)3
Q.9.
If 2.5kW power is transmitted through a 10Ω line at 22000Volt, the power loss in the form of heat will be [ AFMC 1998]
-
14%
a)100 watt
-
43%
b) 10 watt
-
14%
c)0.1 watt
-
29%
d)1 watt
Q.10.
A relation between Faraday's constant F, chemical equivalent E and Electrochemical equivalent Z [ AFMC 2000]
-
0%
a) F=EZ2
-
14%
b) F=E / Z2
-
43%
c)F=E2 / Z
-
43%
d)F=E / Z
Q.11.
Three equal resistors are connected as shown in figure. The maximum power consumed by each resistor is 18 watt. Then maximum power consumed by the combination is [ AFMC 2001]
-
43%
a) 36 watt
-
29%
b) 18 watt
-
14%
c)27 watt
-
14%
d)54 watt
Q.12.
The filament of bulb is made of :.. [ AFMC 2003]
-
11%
a) mercury
-
11%
b) copper
-
67%
c) tungsten
-
11%
d) none of these
Q.13.
Current provided by battery is maximum when ... [ AFMC 2004]
-
43%
a)internal resistance is equal to external resistance
-
29%
b) internal resistance is greater than external resistance
-
29%
c)internal resistance is less than external resistance
-
0%
d)none of these
Q.14.
The mass of product liberated on anode in an electrochemical cell depends upon [ AIEEE 2002]
-
29%
a) ( It)2
-
43%
b) It
-
14%
c)I/t
-
14%
d)I2t
Q.15.
A heater coil connected to a supply of a 220V is dissipating some power PThe coil is cut into two halves and the two halves are connected in parallel. The heater now dissipates a power PThe ratio of P1: P2 is . [ AFMC 2004]
-
40%
a) 2:1
-
10%
b) 1:2
-
40%
c)1:4
-
10%
d)4:1
Q.16.
Which of the following is secondary cell [ AFMC 2004]
-
33%
a)Voltaic cell
-
17%
b) Daniell cell
-
33%
c)Leclanche cell
-
17%
d)Edison cell
Q.17.
Five equal resistors when in series dissipated 5 watt power. If they are connected in parallel, the power dissipated will be [ AFMC 2009]
-
29%
a) 25 watt
-
29%
b) 50 watt
-
29%
c) 100 watt
-
14%
d) 125 watt
Q.18.
Two identical galvanometers are taken, one is to be converted into an ammeter and other into a milliammeter. Shunt of milliammeter compared to ammeter is [AIIMS 1999]
-
17%
a) less
-
67%
b) more
-
17%
c)zero
-
0%
d)none of these
Q.19.
A current of 2A passing through a conductor produces 80J of heat in 10 sec's. The resistance of conductor in ohm is ..[ CBSE-PMT 1989]
-
40%
a) 0.5
-
40%
b) 2
-
0%
c)4
-
20%
d)20
Q.20.
Two identical batteries each of e.m.f 2V and internal resistance 1Ω are available to produce heat in an external resistance by passing a current through it. The maximum power that can be developed across R using these batteries is [1990]
-
40%
a) 3.2W
-
20%
b) 2.0 W
-
20%
c) 1.28W
-
20%
d) (8/9) W
Q.21.
Faraday's laws are consequence of conservation of ..{CBSE PMT 1991]
-
25%
a) Energy
-
25%
b) energy and magnetic field
-
12%
c) charge
-
38%
d) magnetic field
Q.22.
In electrolysis, the amount of mass deposited or liberated at an electrode is directly proportional to [ CBSE-PMT 2000]
-
12%
a)square of electric charge
-
50%
b) amount of charge
-
12%
c)square of current
-
25%
d)concentration of electrolyte
Q.23.
A heating coil is labeled 100W, 220V. the coil is cut in half and the two pieces are joined un parallel to the same source. the energy now liberated per second is ... [ CBSE-PMT 1995]
-
0%
a) 25J
-
20%
b) 50J
-
60%
c)200J
-
20%
d)400J
Q.24.
Forty electric bulbs are connected in series across a 220V supply. After one bulb is fused the remaining 39 are connected again in series across the same supply. The illumination will be.. [ CBSE-PMT1989]
-
40%
a) more with 40 bulbs than with 39
-
40%
b) more with 39 bulbs than with 40
-
20%
c)equal in both the cases
-
0%
d)in the ratio 402 : 392
Q.25.
Direct current is passed through a copper sulphate solution using platinum electrodes. The elements liberated at the electrodes are ... [ CBSE-PMT 1993]
-
25%
a) copper at anode and sulphur at cathode
-
25%
b) sulphur at anode an copper at cathode
-
50%
c) oxygen at anode and copper at cathode
-
0%
d) copper at anode and oxygen at cathode
Q.26.
If the resistance of a conductor is 5 Ω at 50°C and 7 Ω at 100°C, then the mean temperature coefficient of resistance ( of material ) is .. [ CBSE-PMT 1996]
-
0%
a)0.001 / °C
-
20%
b) 0.004 / °C
-
40%
c)0.006 / °C
-
40%
d)0.008 / °C
Explanation
Q.27.
A 100 W and 200 V bulb is connected to a 160V power supply. The power consumption would be .. [ CBSE-PMT 1997]
-
11%
a) 125 W
-
44%
b) 100 W
-
22%
c)80 W
-
22%
d)64 W
Q.28.
Three equal resistors connected across a source of e.m.f. together dissipate 10 watts if same resistors are connected in parallel across the same source of e.m.f what will be the power dissipated? [ CBSE-PMT 1998]
-
22%
a) 10
-
22%
b) 10/3
-
33%
c)30
-
22%
d)90
Q.29.
If nearly 105 coulombs liberate 1 gm equivalent of aluminum, then the amount of aluminum ( equivalent weight 9), deposited through electrolysis in 20 minutes by a current of 50amp will be... [ CBSE PMT 1998]
-
33%
a) 0.6 gm
-
8%
b) 0.09 gm
-
42%
c) 5.4 gm
-
17%
d) 10.8 gm
Q.30.
Si and Cu are cooled to a temperature of 300K then resistivity? [ CBSE-PMT 2001]
-
0%
a) For Si increases and for Cu decreases
-
33%
b) For Cu increases and for Si decreases
-
0%
c)Decreases fro both Si and Cu
-
67%
d)Increases for both Si and Cu