The resistance across AB is
4 Ω
1Ω
2 Ω
1.5 Ω
Heat produced in a current carrying wire in 5s is 60 J. The same current is passed through another wire of half the resistance. What is the heat produced in 5 s.
60J
30J
15J
120J
What is the potential difference, in volts, required to pass a current of 3 A through a resistor of 6 ohms?
3 Volts
120 Volts
18 Volts
180 Volts
The quantity of heat generated in a conductor when a current flows through it is directly proportional to the (a) resistance of the conductor. (b) current carried by the conductor. (c) time for which the current flows
a,b and c
a and b only
b and c only
a and c only
A current of 5A is passed through a resistance of 84 Ω. Calculate the amount of heat given out by it in one minute? (J = 4.2 joules/ calories).
6000 calories
30,000 calories
500 calories
1,26,000 calories
Two light bulbs P and Q are identical in all respects, except that P's filament is thicker than Q's. If the same potential difference is applied to each, then
P will burn brighter because it has the greater resistance.
Q will burn brighter because it has the greater resistance.
P will burn brighter because it has the lower resistance
Q will burn brighter because it has the lower resistance
Resistance changes electricity to heat. Which of these appliances uses this property?
A VCR
An electric fan
A toaster
A Washing machine
What is the maximum power that an appliance should have if it is connect to a 230V supply by a 5A cable .
46W
1.15 KW
115W
4.6 KW
In the circuit shown the bulb marked 2R has twice the resistance of the bulb marked R. Compared with bulb 2R, the current in bulb R and its brightness compared to the other bulb, is
Larger current in R brighter 2R
Larger current in R dimmer 2R
Smaller current in R brighter 2R
Smaller current in R dimmer 2R
Two light bulbs are marked 230 V; 75 W and 230 V; 150 W. If the first bulb has a resistance R, then what is the resistance of the second bulb?
¼ R
½ R
2 R
4R