(English Medium) ICSE Class 10 - CISCE Question Bank Solutions

An electric iron is rated at 230 V, 750 W. What is its resistance? What maximum current can be passed through it?

An electric bulb is rated as 100W – 250V. What information does it convey? Calculate the resistance of its filament while glowing.

An electric bulb is rated as 100W – 250V. What information does it convey? Calculate the current through the filament of the bulb.

An Electric bulb is marked 100 W, 230 V. What find the energy consumed by the bulb in one hour.

An Electric bulb is marked 100 W, 230 V. What current does it take?

An Electric bulb is marked 100 W, 230 V. What how long would this lamp take to consume one unit of electricity?

Out of the three fuses with current ratings 5A, 10A, 15A, which one is to be connected in a geyser circuit marked 3 kW, 220V? Give reason for your answer.

The equation I²R seems to suggest that the rate of heating in a resistor is reduced if resistance decreases, whereas equation P = V²/R suggests just the opposite. How do you reconcile this problem?

Two resistances R₁ = 4Ω and R₂ = 6Ω are connected in series. The combination is connected with a battery of e.m.f. 6V and negligible resistance. Calculate:
(i) the heat produced per minute in each resistor,
(ii) the power supplied by the battery.

A bulb is connected to a battery of e.m.f. 6V and internal resistance 2Ω A steady current of 0.5A flows through the bulb. Calculate the total energy supplied by the battery in 10 minutes.

A bulb is connected to a battery of e.m.f. 6V and internal resistance 2Ω A steady current of 0.5A flows through the bulb. Calculate the resistance of the bulb.

A bulb is connected to a battery of e.m.f. 6V and internal resistance 2Ω A steady current of 0.5A flows through the bulb. Calculate the heat energy dissipated in the bulb in 10 minutes.

A battery of e.m.f. 12V and internal resistance 1.6 Ω is connected to two resistors of 4Ω and 6Ω connected in parallel. Calculate:
(i) the current drawn from the battery,
(ii) the power dissipated in each resistor,
(ii)the total power supplied by the battery.

A bulb is marked 100W, 220V and an electric heater is marked 2000 W, 220 V.
(i) What is the ratio between the resistances of these two devices?
(ii) How does the power-voltage rating of a device help us to decide about the type of leads (connecting wires) to be used for it?
(iii) In which of the above two devices, a thicker connecting wire of lead is required?

An immersion rod having resistance of 50 Ω is connected to 220V main supply. Assuming that all the energy generated goes to heat the water, calculate the time taken to heat 5 kg water from 30°C to 100°C.

A house is provided with 15 bulbs of 40W, 5 bulbs of 100W, 5 fans of 80 W, and one heater of 1.0 kW. Each day bulbs are used for 4h, fans for lOh, and heater for 2h. The voltage of mains is 220 V. Calculate:
(i) Maximum power of the circuit in the house,
(ii) maximum current capacity of the main fuse in the house,
(iii) the electrical energy consumed in a week,
(iv) cost of electricity consumed at 1.25 Rs. per kWh.

Two bulbs are rated: bulb A 100W, 120 V bulb B 10W, 120 V. If both are connected across a 120V supply, which bulb will consume more energy, When in series? Also calculate the current through each bulb in above cases.

Two bulbs are rated: bulb A 100W, 120 V bulb B 10 W, 120 V. If both are connected across a 120V supply, which bulb will consume more energy, When in parallel? Also calculate the current through each bulb in the above cases.

A. bulb is rated at 100W, 250V and another one at 60W, 250V. What is the current flowing in the circuit if the two bulbs are put in series across a 220 V mains supply?

The resistance of filament of an electric heater is 500 Ω It is operated at 200V for 1 hour daily. Calculate the current drawn by the heater and the energy consumed in joule.