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(SOLVED)
Note : All Answers are in red.
1. If 2 bulbs rated 2.5 W - 110 V and 100 W - 110 V are connected in series to a 220 V supply then
2.5 W bulb will fuse
100 W bulb will fuse
both will fuse
both will not fuse
2. A rectangular carbon block has dimensions 1.0 cm � 1.0 cm � 50 cm. Resistances are measured, first across two square ends and then across two rectangular ends, respectively. If resistivity of carbon is 3.5 � 10-5 Ω-m, then values of measured resistances respectively are:
� 10-2 Ω, 7 � 10-5 Ω
7 � 10-5 Ω, 
� 10-2 Ω
� 10-4Ω, 7 � 10-7 Ω
Ω, 7 � 10-2 Ω
3. The conductivity current density in a wire is 10 A/cm2 and the electric field in the wire is 5 V/cm. If ρ = resistivity of material, s = of the material then (in S.I. units):
ρ = 5 x 10-3
ρ = 200
s = 5 x 10-3
s = 100
4. In an electric circuit containing a battery, the positive charge inside the battery
always goes from the positive terminal to the negative terminal
may go from the positive terminal to the negative terminal
always goes from the negative terminal to the positive terminal
does not move.
5. If internal resistance of a cell is proportional to current drawn from the cell. Then the best representation of terminal potential difference of a cell with current drawn from cell will be:
- Ans
6. 
In which of the above cells, the potential difference between the terminals of a cell exceeds its emf.
a
b
c
d
7. A resistor of resistance R is connected to a cell of internal resistance 5 Ω. The value of R is varied from 1 Ω to 5 Ω. The power consumed by R:
increases continuously
decreases continuously
first decreases then increases
first increases then decreases.
8. A bulb is connected to a battery of emf 10 V so that the resulting current is 10 mA. When the bulb is connected to 220 V mains, the current is 50 mA. Choose the correct alternative (s)
In the first case, the resistance of the bulb is 1kΩ and in second case, it is 4.4 kΩ.
It is not possible since ohm's law is not followed
the increase in resistance is due to heating of the filament of the bulb when it is connected to 120 V mains
None of these
9. Choose the incorrect alternatives
It is easier to start a car engine on a warm day than on a chilly cold day because the internal resistance of battery decreases with rise in temperature
It is more economical to transmit electric power at high voltage and low current rather than at low voltage and high current because heat loss is proportional to square of current.
The heating coil of an electric iron is enclosed in mica sheets because mica is a bad conductor of heat and good conductor of electricity
The heating coil of an electric iron is enclosed in mica sheets because mica is a good conductor of heat and bad conductor of electricity.
10. In the ladder network shown, current through the resistor 3 Ω is 0.25 A. The input voltage
10 V
20 V
5 V
V
