Advertisements
Advertisements
Question
An electric bulb is rated 250 W, 230 V.
- the energy consumed in one hour, and
- the time in which the bulb will consume 1.0 kWh energy when connected to 230 V mains.
Advertisements
Solution
(i) Given, Power (P) = 250 W, Voltage (V) = 230 V, Time (t) = 1 h = 3600 sec, Energy (E) = ?
Energy, E = P × t
Substituting the values in the formula above, we get,
E = 250 × 3600
E = 9 × 105 J
(ii) Let t be the time in which the bulb will consume 1.0 kWh energy when connected to 230 V mains.
P = 1.0 kWh = 1000 Wh
Substituting the value in the formula, we get,
⇒ 1000 = 250 × t
⇒ t = `1000/250`
⇒ t = 4 h
Hence, time = 4 h
RELATED QUESTIONS
Which particles constitute the electric current in a metallic conductor?
In the circuit diagram given below five resistances of 10 Ω, 40 Ω, 30 Ω, 20 Ω, and 60 Ω are connected as shown to a 12 V battery.
Calculate:
(a) total resistance in the circuit.
(b) total current flowing in the circuit.
Ten bulbs are connected in a series circuit to a power supply line. Ten identical bulbs are connected in a parallel circuit to an identical power supply line.
(d) Which circuit would have less current in it?
State three factors on which the heat produced by an electric current depends. How does it depend on these factors?
Define the term resistivity.
Electrical appliances have voltage and power ratings as listed below. Which
has the larger working resistance?
| Appliances | Voltage (V) | Power (W) |
| (a) Washing machine | 250 | 3000 |
| ( b) Television | 240 | 160 |
| (c)240 | 240 | 1500 |
| ( d) Hair curler | 250 | 20 |
| ( e) Car head lamp | 12 | 36 |
A bulb is connected to a battery of p.d. 4 V and internal resistance 2.5 Ω . A steady current of 0.5 A flows through the circuit. Calculate:
The total energy supplied by the battery in 10 minutes
Which of the following represents voltage?
