Advertisements
Advertisements
प्रश्न
Water in an electric kettle connected to a 220 V supply took 5 minutes to reach its boiling point. How long will it take if the supply voltage falls to 200 V?
Advertisements
उत्तर
P = `"V"^2/"R"`
Heat gained = `("V"^2)/"R" xx "t"`
`("V"_1^2/"R") xx "t"_1 = ("V"_2^2/"R") xx "t"_2`
t2 = `("V"_1/"V"_2)^2 xx "t"_1`
`= (220/200)^2 xx 300 = 363 "s"`
= 6.05 min
APPEARS IN
संबंधित प्रश्न
Name two safety devices which are connected to the live wire of a household electric circuit
A current of 0.2 A flows through a wire whose ends are at a potential difference of 15 V.
calculate:
(i) the resistance of the wire and
(ii) the heat energy produced in 1 minute.
Tick(✓) the correct choice in the following:
In the circuit shown in the following fig, the e.m.f. of the cell is 4 volts, the current
flowing through the resistor is
Point out two main disadvantages of ‘Tree System’.
Name two common material used for heating elements.
Of the three connecting wires in a household circuit: Which two of the three wires are at the same potential? In which of the three wires should the switch be connected?
A family uses a light bulb of 100W, a fan of 100W, and a heater of 1000W, each for 8 hours a day. If the cost of electricity is Rs. 2 per unit, what is the expenditure to the family per day, on electricity?
Out of the three fuses with current ratings 5A, 10A, 15A, which one is to be connected in a geyser circuit marked 3 kW, 220V? Give reason for your answer.
In the given figure, the emf of the cell is 2.2 V, and if internal resistance is 0.6 Ω. Calculate the power dissipated in the whole circuit.
