Question

A bulb of 50 W, 10 V is operated at 100 V supply.
If bulb glows with full intensity, then used
resistance in series is
(1) 18 2
(2) 92
(4) 1.8 2
(3) 10 2​

Answer 1

The resistance is 18 ohm and 2 ohm.

(I) is correct option.

Explanation:

Given that,

Power = 50 W

Voltage = 100 V

We need to calculate the current

Using formula of current

$P=I\times V$

$I=\dfrac{P}{V}$

Put the value into the formula

$I=\dfrac{50}{10}$

$I=5\ A$

We need to calculate the resistance

Using ohm's law

$V=IR$

$R=\dfrac{V}{I}$

Put the value into the formula

$R=\dfrac{10}{5}$

$R=2\ \Omega$

Now the circuit will contain 100 V power supply in series with above bulb and another resistor R and lamp requires 5 amps of current to flow in the circuit.

We need to calculate the total resistance

Using formula of resistance

$R'+2=\dfrac{V}{I}$

Put the value into the formula

$R'+2=\dfrac{100}{5}$

$R'=20-2$

$R'=18\ \Omega$

Hence, The resistance is 18 ohm and 2 ohm.

Learn more :

Topic : resistance

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Answer 2

Answer:

the answer is 18 ohm

Explanation:

rhe answer is 18