Question

The torch bulb is rated at 2.5 v and 500ma find the power and resistance

Answer 1

Given,

V = 2.5 V

I = 500 mA

We are given to find the power P and resistance R of the torch bulb.

So we may use the formulae,

1.  P = VI

2. R = V / I

But before, have a look at the given current. It's in mA (milli Ampere). We have to convert this to Ampere.

    1 mA = 1 / 1000 A

⇒  500 mA = 500 / 1000 = 0.5 A

Hence,  I = 0.5 A.

Now,

→  P = VI = 2.5 × 0.5 = 1.25 W

→  R = V / I = 2.5 / 0.5 = 5 Ω

Hence the power and resistance are 1.25 W and 5 Ω respectively.

Answer 2

Answer:

power = 1.25W. and. resistance = 5ohm