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प्रश्न
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उत्तर
This is done to protect the appliances and circuits from any damage due to short-circuit and thus accidents like fire and fatal shocks. Earthing provides an easy and safe path to the excess current in the circuit and sends it to the ground.
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संबंधित प्रश्न
An electric circuit consisting of a 0.5 m long nichrome wire XY, an ammeter, a voltmeter, four cells of 1.5 V each and a plug key was set up.
(i) Draw a diagram of this electric circuit to study the relation between the potential difference maintained between the points 'X' and 'Y' and the electric current flowing through XY.
The lamps in a house hold circuit are connected in parallel because:
(a) this way they required less current
(b) if one lamp fails the others remain lit
(c) this way they require less power
(d) if one lamp fails the other also fail
Complete the following sentence:
Fuse wire has a ............ Melting point and it is made of an alloy of ......... and if the current in a circuit rises too high, the fuse wire ...........
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?
The circuit diagram (Fig.) shows a battery of e.m.f. 6 volts and internal
resistance of 0.8 Ω oonnected in series. Find the
(a) Current reoorded by the ammeter,
(b) P.d. across the terminals of the resistor B,
( c) Current passing through each of the resistors B, C and D, and
( d) P.d. across the terminals of the battery.
What is the criteria for selecting a fuse wire?
60 joules of heat was dissipated in a resistor when 20 C flowed for 5 s. Calculate:
(a) P.d. across the resistor,
(b) Resistance of the resistor, and
(c) Average power dissipated in the resistor.
Explain with the help of a diagram how does 'short circuiting' occur in an electric kettle.
A geyser is rated 1500 W, 250 V. This geyser is connected to 250 V mains. Calculate:
- The current drawn,
- The energy consumed in 50 hours, and
- The cost of energy consumed at ₹ 4.20 per kWh.
Match the items in column-I to the items in column-II:
| Column - I | Column - II | ||
| (i) | electric current | (a) | volt |
| (ii) | potential difference | (b) | ohm meter |
| (iii) | specific resistance | (c) | watt |
| (iv) | electrical power | (d) | joule |
| (v) | electrical energy | (e) | ampere |
