A wire of a certain material is streched slowly by ten per cent. Its new resistance and specific resistance become respectively
(1) 1.2 times, 1.1 times
(2) 1.21 times,same
(3) both remain the same
(4) 1.1 times, 1.1 times
An electric kettle takes 4 A current at 220 V. How much time will it take to boil 1 kg of water from temperature C? The temperature of boiling water is C
(a) 6.3 min
(b) 8.4 min
(c) 12.6 min
(d) 4.2 min
A cell can be balanced against 110cm and 100 cm of potentiometer wire, respectively with and without being short-circuited through a resistance of . Its internal resistance is
(1) 1.0
(2) 0.5
(3) 2.0
(4) zero
In the circuit shown, the current through the 4 resistor is 1 A when the points P and M are connected to a DC voltage source. The potential difference between the points M and N is
1. 1.5 V
2. 1.0 V
3. 0.5 V
4. 3.2 V
A capacitor of capacitance 5 μF is connected as shown in the figure. The internal resistance of the cell is 0.5 Ω. The amount of charge on the capacitor plate is?
(1) 0 μC
(2) 5 μC
(3) 10 μC
(4) 25 μC
In the circuit here, the steady state voltage across capacitor C is a fraction of the battery e.m.f. The fraction is decided by
(1) R1 only
(2) R1 and R2 only
(3) R1 and R3 only
(4) R1, R2 and R3
In the figure below, what is the potential difference between the point A and B and between B and C respectively in steady state
(1)
(2)
(3)
(4)
In the given figure each plate of capacitance C has partial value of charge equal to:
1. CE
2.
3.
4.
The plates of a capacitor are charged to a potential difference of 320 volts and are then connected across a resistor. The potential difference across the capacitor decays exponentially with time. After 1 second the potential difference between the plates of the capacitor is 240 volts, then after 2 and 3 seconds the potential difference between the plates will be
(1) 200 and 180 V
(2) 180 and 135 V
(3) 160 and 80 V
(4) 140 and 20 V
Three identical capacitors are given a charge Q each and they are then allowed to discharge through resistance R1, R2 and R3. Their charges, as a function of time shown in the graph below. The smallest of the three resistance is
(1) R3
(2) R2
(3) R1
(4) Cannot be predicted