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12th CBSE
IMPORTANT
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A 500 W electric heater is designed to work with a 200 V line. If the voltage of the line drops to 160 V, then what will be the percentage loss of the heat developed?

Important Questions on Current Electricity

EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 16
A 50 W bulb is connected in a 200 V line. Determine the current flowing in it and its resistance.
EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 17
Two bulbs rated 25 W, 220 V and 100 W, 220 V are connected in series to a 440 V supply. Show with necessary calculations which bulb if any will fuse.
EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 17
Two bulbs rated 25 W, 220 V and 100 W, 220 V are connected in series to a 440 V supply. What will happen if the two bulbs are connected in parallel to the same supply?
EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 18
A servo voltage stabilizer restricts the voltage output to 220 V ±1%. If an electric bulb rated at 220 V, 100 W is connected to it, what will be the minimum and maximum power consumed by it?
EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 19
A room is lighted by 200 W, 124 V incandescent lamps fed by a generator whose output voltage is 130 V. The connecting wires from the generator to the user are made of aluminium wire of total length 150 m and cross‐sectional area 15 mm2. How many such lamps can be installed? Specific resistance of aluminium =2.9×10−8 Ω m.
MEDIUM
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 20
Two wires A and B of same material and mass, have their lengths in the ratio 1:2. On connecting them, one at a time to the same source of emf, the rate of heat dissipation in B is found to be 5 W. What is the rate of heat dissipation in A?
EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 21
An electric heater and an electric bulb are rated 500 W, 220 V and 100 W, 220 V respectively. Both are connected in series to a 220 V d.c. mains. Calculate the power consumed by the heater.
EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 21
An electric heater and an electric bulb are rated 500 W, 220 V and 100 W, 220 V respectively. Both are connected in series to a 220 V d.c. mains. Calculate the power consumed by the electric bulb.