Advertisements
Advertisements
Question
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.
Advertisements
Solution
Given: R= 500 Ω, V = 200 volt.
Total time = t = 1 × 30h = 30h = 30 × 60 = 60 s = 108000s.
Current drawn by the heater I = `"V"/"R" = 200/500 = 0.4` A
The energy consumed (in joule) = `"V"^2/"R" "t"`
`= (200)^2/500 xx 108000`
= 8640000 J.
RELATED QUESTIONS
A geyser is rated 1500 W, 250 V. This geyer is connected to 250 V mains. Calculate:
(i) the current drawn
(ii) the energy consumed in 50 hours, and
(iii) the cost of energy consumed at Rs. 4.20 per kWh
The diagram above shows a circuit with the key k open. Calculate :
(i) the resistance of the circuit when the key k is open.
(ii) the current drawn from the cell when the key k is open.
(iii) the resistance of the circuit when the key k is closed.
(iv) the current drawn from the cell when the key k is closed.
Which cable, one rated 15A and the other rated 5A will be thicker? Give a reason.
‘The current rating of a fuse is 5A’. Comment on this statement.
Two electric lamps each rating 100 W, 110 V are connected in series to a 220 V power supply and two other electric lamps each of marking 100 W, 220 V are connected in parallel to the same power supply. Will anyone of the two combinations give more light than the other? Give a reason for your answer.
An Electric bulb is marked 100 W, 230 V. What how long would this lamp take to consume one unit of electricity?
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?
1 mV is equal to:
An overhead tank of capacity 10 k litre is kept at the top of building 15 m high. Water falls in tank with speed 5`sqrt2` m/s. Water level is at a depth 5 m below ground. The tank is to be filled in `1/2` hr. If efficiency of pump is 67.5% electric power used is ______ W.
