Advertisements
Advertisements
प्रश्न
State three factors on which the heat produced in a metallic wire due to passage of current in it depends.
Advertisements
उत्तर
(i) On resistance of wire.
(ii) On strength of current through the wire.
(iii) On time for which the current flows in the wire.
संबंधित प्रश्न
Calculate the cost of operating a heater of 500 W for 20 hours at the rate of Rs 3.90 per unit.
In a filament type light bulb, most of the electric power consumed appears as:
(a) visible light
(b) infra-red-rays
(c) ultraviolet rays
(d) fluorescent light
Name the S.I unit of electrical energy. How is it related to Wh?
An electric bulb is rated ‘100 W, 250 V’. How much current will the bulb draw if connected to a 250 V supply?
The diagram shows a coil connected to a center zero galvanometerG . The galvanometer shows a deflect ion to the right when the north pole N of a powerful magnet is moved to the right as shown .
(i) Explain, why the defelct ion occurs in the galvanometer.
(ii ) State whether th e current in the coil is cl ockwise or anticl ockwise
when viewed from the end P.
(iii ) State th e observation in G when the coil is moved away from north
pole N of the magnet keeping the magnet stationary.
(iv)State the observation in G when both the coil and the magnet are
moved to right at th e same speed .
What does the unit kilowatt hour measure? Define it.
Why is heating element wound on a long porcelain rod in a room heater.
Two resistances R1 = 4Ω and R2 = 6Ω are connected in series. The combination is connected with a battery of e.m.f. 6V and negligible resistance. Calculate:
(i) the heat produced per minute in each resistor,
(ii) the power supplied by the battery.
A bulb is marked 100W, 220V and an electric heater is marked 2000 W, 220 V.
(i) What is the ratio between the resistances of these two devices?
(ii) How does the power-voltage rating of a device help us to decide about the type of leads (connecting wires) to be used for it?
(iii) In which of the above two devices, a thicker connecting wire of lead is required?
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?
