Two electric bulbs rated for the same voltage have power of 200 watt and 100 watt. If their resistances are respectively R1 and R2 then ____.
R1 = 2R2
R2 = 2R1
R2 = 4R1
R1 = 4R2
The terminal potential difference of a cell is greater than its e.m.f. when it is ____.
being discharged
in open circuit
being charged
being either charged or discharged
For which of the following, dependence of drift velocity vd on electric field E is Ohm’s law obeyed?
1 volt equals ____.
1 J
1 C/J
1 J/C
None of these
In comparing e.m.f two cells with the help of a potentiometer, at the balance point, the current flowing through the wire is taken from ____.
one of these cells
both of these cells
the battery in the circuit
none of these
A battery of 20 cells (each having e.m.f. 1.8 volt and internal resistance 0.1 ohm) is charged by 220 volts and the charging current is 15A. The resistance to be put in the circuit is ____.
10.27 ohms
12.27 ohms
8.62 ohms
16.24 ohms
A battery of 20 cells (each having e.m.f. 1.8 volt and internal resistance 0.1 ohm) is charged by 220 volts and the charging current is 15A. Total power obtained from mains is ____.
6600W
3300W
540W
276E
A primary cell has e.m.f.2 volts. When short circuited it gives a current of 4 amperes, Its internal resistance in ohms will be ____.
0.5
2
5
8
Good conductors have many loosely bound ____.
atoms
protons
molecules
electrons
The value of current i in the given circuit is ____.
zero
5 amp
7 amp
11 amp