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
What Makes an Electric Current Flow in a Wire?
Why should the resistance of:
an ammeter be very small?
If a charge of 420 C flows through a conducting wire in 5 minutes what is the value of the current?
Tick(✓) the correct choice in the following:
A three pin plug is connected to the lead for a 1 kW electric iron to be
used on a 250 V supply. Which of the following statements is not correct?
If the potential differences between two parts of a thundercloud is 10s V,
what is the amount of energy given up during the passage of 20 coulombs?
(a)2x10-7J
(b)200J
(c)Sx106 j
(d)2x 109J
(e)2x 1010 J
State the condition when it is advantageous to connect cells in series.
An electrical gadget can give an electric shock to its user under certain circumstances. Mention any two of these circumstances.
Define an electric current.
