Two identical batteries each of emf 2 V and internal resistance 1 Ω 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
3.2 W
2.0 W
1.28 W
A heating coil is labelled 100 W, 220 V. The coil is cut in two equal- halves and the two pieces are joined in parallel to the same source. The energy now liberated per second is
25 J
50 J
200 J
400 J
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 willbe
More with 40 bulbs than with 39
More with 39 bulbs than with 40
Equal in both the cases
In the ratio 402 :392
Two bulbs 25 W, 220 V and 100 W, 220 V are given. Which has higher resistance?
25 W bulb
100 W bulb
Both bulbs will have equal resistance
Resistance of bulbs cannot be compared
A 5°C rise in temperature is observed in a conductor is doubled, the rise in temperature will be approximately
16°C
10°C
20°C
12°C
A steady current of 1.5 A flows through a copper voltameter for 10 min. If the electrochemical equivalent of copper is 30 x 10-5 g C-1 the mass of copper deposited on the electrode will be
0.40 g
0.50 g
0.67 g
0.27 g
A current of 2 A, passing through a conductor produces 80 J of heat in 10 s. The resistance of the conductor in ohm is
0.5
2
4
20
Faraday's laws are consequence of conservation of
Energy
Energy and magnetic field
Charge
Magnetic field
Two 220 V, 100 W bulbs are connected first in series and then in parallel. Each time the combination is connected to a 220 V AC supply line. The power drawn by the combination in each case respectively will be
200 W, 150 W
50 W, 200 W
50 W, 100 W
100 W, 50 W
If the cold junction of a thermocouple is kept at 0oC and the hot junction is kept at T0C, then the relation between neutral temperature (Tn) and temperature of inversion (Ti) is
Tn = 2Ti
Tn = Ti – T
Tn = Ti + T
