When three identical bulbs are connected in series, the consumed power is \(10\) W. If they are now connected in parallel then the consumed power will be:
1. \(30\) W
2. \(90\) W
3. \(\frac{10}{3}\) W
4. \(270\) W
In a hot wire ammeter due to the flowing of the current, the temperature of the wire is increased by \(5^{\circ}\) C. If the value of the current is doubled, then the increase in temperature will be:
1. \(15^{\circ}\) C
2. \(20^{\circ}\) C
3. \(25^{\circ}\) C
4. \(30^{\circ}\) C
If the power dissipated in \(5~\Omega\) is \(20\) W then the power dissipated in \(4~\Omega\) is:
1. \(4\) W
2. \(6\) W
3. \(10\) W
4. \(20\) W
If there are two bulbs of (\(40~\text{W},200~\text{V}\)), and (\(100~\text{W},200~\text{V}\)), then the correct relation for their resistance is:
1. \(R_{40}<R_{100}\)
2. \(R_{40}>R_{100}\)
3. \(R_{40}=R_{100}\)
4. no relation can be predicted
Two \(220\)-volts, \(100\)-watts bulbs are connected first in series and then in parallel. Each time the combination is connected to a \(220\)-volts AC supply line. The power drawn by the combination in each case respectively will be:
1. \(50\) watts, \(100\) watts
2. \(100\) watts, \(50\) watts
3. \(200\) watts, \(150\) watts
4. \(50\) watts, \(200\) watts
An electric kettle has two heating coils. When one of the coils is connected to an a.c. source, the water in the kettle boils in \(10\) minutes. When the other coil is used the water boils in \(40\) minutes. If both the coils are connected in parallel, the time taken by the same quantity of water to boil will be:
1. \(8\) min
2. \(4\) min
3. \(25\) min
4. \(15\) min
A fuse wire is a wire of:
1. high resistance and high melting point
2. high resistance and low melting point
3. low resistance and low melting point
4. low resistance and high melting point
When three identical bulbs of \(60\) watts and \(200\)-volt rating are connected in series to a \(200\)-volt supply, the power drawn by them will be:
1. \(180\) watts
2. \(10\) watts
3. \(20\) watts
4. \(60\) watts
In India electricity is supplied for domestic use at \(220\) V. It is supplied at \(110\) V in the USA. If the resistance of a \(60\) W bulb for use in India is \(R\), the resistance of a \(60\) W bulb for use in the USA will be:
1. | \(2R\) | 2. | \(\dfrac{R}{4}\) |
3. | \(\dfrac{R}{2}\) | 4. | \(R\) |