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

How does earthing prevent electrical shock?

You are required to connect a bulb, a fan and a socket outlet to the mains in one set A and an air-conditioner and a refrigerator to the mains in other set B. Will you recommend the wire of same thickness and same insulation in both? explain your answer.

At what voltage is the electric power generated at the generating station? Explain the transmission of this power to your house.

How is the amount of heat produced calculated due to the passage of current in a metallic conductor? Derive an expression for it.

Three 250 W heaters are connected in parallel to a 100 V supply, Calculate total current taken from the supply.

Three 250 W heaters are connected in parallel to a 100 V supply, Calculate the resistance of each heater.

Three 250 W heaters are connected in parallel to a 100 V supply, Calculate the energy supply in kWh to the three heaters in 5 hour.

An electric bulb is rated 240V-60W and is working at 100% efficiency.
(i) Calculate the resistance of bulb.
(ii) (a) Draw the circuit diagram.
(b) What is the rate of conversion of energy in each bulb?
(c) Total power used by the bulbs.

With reference to the diagram shown below calculate:

(i) The equivalent resistance between P and Q.
(ii) The reading of ammeter.
(iii) The electrical power between P and Q.

State other bigger units of electric power and express them in watt.

State (i) the S. I. unit, (ii) the household unit, of electrical energy. How are these units related?

An electric kettle is rated 3kW, 250V. What should be the current capacity of the fuse with it?

I ampere of current is passed through a resistor of resistance R ohm for time t second. Obtain expression for
(i) the electrical energy, and
(ii) the electrical power spent.

How can electric energy consumed by an electric appliance be calculated in kilowatt hour (kWh)?

What is the resistance of an appliance rated at V volt, P watt?

A family uses a light bulb of 100W, a fan of 100W, and a heater of 1000W, each for 8 hours a day. If the cost of electricity is Rs. 2 per unit, what is the expenditure to the family per day, on electricity?

Establish the relation that heat produced in a metallic conductor due to the flow of current is V²t/R joules, where V is the potential difference across the ends of the conductor, R its resistance and t is the time in second for which current flows.

Find the heat produced in joules when a current of 10 amperes flows through a connecting wire of resistance 2 × 10^-2 ohms and heating element of resistance 250 ohms for 2 seconds.

An electric lamp A of 40 W and another electric lamp B of 100 W are connected to 220 V supply. Calculate the ratio of their filament resistances?

Find the energy released by a current of 0.25 amperes flowing through a heater for 5 minutes. The p.d. is 230 V.