Question

a boy does work's of 100j in 2s and 400j in 20s in as find the
ration the power done
by the boy in
these two cases.
​

Answer 1

Answer:

Work Done 1 = 100J

Time 1 = 2 s

Power 1 = 100/2 W

= 50 W

Work Done 2 = 400J

Time 2 = 20 s

Power 2 = 400/20 W

= 20 W

Power 1 : Power 2 = 50/20

= 5:2

I hope this helps.

Answer 2

Answer:

Step 1: Calculate the potential difference using formula of work done.

By formula,

W=QV (where, W is the work done, V is the voltage or the potential difference and Q is the charge)

4000=10×V

⇒V

=400v

Step 2: Calculate the current.

From Ohm’s law, we can write,

V=IR (where, I is the current)

⇒I=

R

V

⇒I=

50

400

⇒I=8Amp

Hence, the current passing through a resistor of 50Ω is 8Amp.

The correct answer is o