An electric iron rated 750 W is operated for 2 hours/day. How much energy is consumed by the electric iron for 30 days?
An electric lamp is labelled 12 V, 36 W. This indicates that it should be used with a 1 V supply. What other information does the label provide?
A current of 2 A is passed through a coil of resistance 75Ω for 2 minutes. (a) How much heat energy is produced? (b) How much charge is passed through the resistance?
What is the resistance, under normal working conditions of a 240 V electric lamp rated at 60 W? If two such lamps are connected in series across a 240 V mains supply, explain why each one appears less bright.
What is wrong with the circuit diagram (Fig. 34)? Carefully check the symbols and assign proper positive and negative signs to them.
A simple electric circuit has 24 V battery and a resistor of 60 Ω. What will be the current in the circuit? The resistance of the connecting wires is negligible.
Two resistors A and B of 4 Ω and 6 Ω respectively are connected in parallel. The combination is connected across a 6 volt battery of negligible resistance. Calculate the power supplied by the battery.
Mention three uses of the carbon arc.
Household wiring for lamp connections can either be done in parallel or in series.Which one would you prefer? Give a reason for your answer.
An electric heater is rated 220 V, 550 W. What does this statement mean?
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?
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.
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 kWh, by the heater in a month of 30 days.
An electric appliance is rated at 1000 W, 250V. Calculate:
(i) The electrical energy consumed by the appliance in 12 hour.
(ii) The cost of energy consumed at Rs. 1.20 per kWh.
How long would this appliance take to use 1 kWh energy when operated at 250 V?
Unit of electric power may also be expressed as:
A student wants to use an electric heater, an electric bulb and an electric fan simultaneously.
How should these gadgets be connected with the mains? Justify your answer giving three reasons.
