Question

Plz solve Q#21 and Q#22...

Answer 1

Hey there!

21) Given,

Mass of man(m) = 50 kg

Height (h) = No. of steps * Each step height = 50 * 10 cm = 500 cm = 5 m

Power(P) = ?

Acceleration due to gravity(g) = 10 m/s²

We know,

Work done = mgh

                   = 50 * 10 * 5

                    = 2500 J

Now,

Power = Work done / time

Power = 2500 / 10

Power = 250 W

Hence, option d. 250 W is correct.

22) Given,

power of each bulb = 25 W

time = 10 h

Total power = 25 * 4 = 100 W = 0.1 kW

Time = 10 h

Electric Energy = Power * time

                          = 0.1 * 10

                         = 1 kWh

                          = 1 unit.

Total unit energy used in month = 1 * 30 = 30 unit

Cost of 1 unit = Rs. 10

Cost of 30 unit = 30 * 10 = Rs. 300

Hope It Helps You!