Question

A 100w bulb is connected to a 250v supply. Determine .A)the current flowing in the bulb,and



b.The resistance of the bulb

Answer 1

Answer:

a.) 0.4A

b.) 625ohms

Explanation:

a.) P=VI

100w=250v*I

100/250=I

I=0.4A

b.) V=IR

250v=0.4A*R

250/0.4=R

R=625ohms

Answer 2

Answer:

A) The current passing through the bulb is 0.4 A.

B) The resistance of the bulb is 625 ohm.

Explanation:

Given,

The power of the bulb (P) is 100 W.

The voltage across the bulb (V) is 250 V.

To find,

A) The current flowing in the bulb.

B) The resistance of the bulb.

Calculation,

When a battery of voltage V is connected to a bulb of resistance R and if 'I' is the current passing through the bulb, then the power of the bulb P is given by:

P = VI...(1)

 (OR)

P = I²R...(2)

A) For finding the current 'I' passing through the bulb we use equation (1)

i.e. P = VI

⇒ 100 W = 250 V × I

⇒ I = 100 W/250 V

⇒ I = 0.4 A

Therefore, the current passing through the bulb is 0.4 A.

B) For finding the resistance of the bulb we can use equation (2)

i.e. P = I²R

⇒ 100 W = 0.4² × R

⇒ 100 W = 0.16 × R

⇒ R = 100/0.16

⇒ R = 625 ohm.

Therefore, the resistance of the bulb is 625 ohm.

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