NCERT Solution for Class 10 Science Chapter 12
Electricity
NCERT Books for Session 2022-2023
CBSE Board and UP Board
Intext Questions
Page No-220
Questions No-2
An electric motor takes 5 A from a 220 V line. Determine the power of the motor and the energy consumed in 2 h.
Share
Power of the electric motor is given by
P = VI
Where, V = 220 V and I = 5 A
So, Power P = 220 × 5 = 1100 W
Now, the energy consumed = Power × time
Where, P = 1100 W
t = 2 hours = 2 × 60 × 60 seconds = 7200 seconds
So, the energy consumed E = 1100 × 7200 J = 7920000 J
For more answers visit to website:
https://www.tiwariacademy.com/ncert-solutions/class-10/science/chapter-12/
Here, I = 5 A, V = 220 V, t = 2h = 7,200 s
Power, P = V I = 220 x 5 = 1100 W
Energy consumed = P x t = 1100 W x 7200 s = 7,920,000 J
Given, Electric current (I) = 5A,
Potential difference (V) = 220V,
Time (t) = 2h = 2 x 60 x 60 s = 7200 s
Power (P) =?
Energy consumed =?
We know that, P = VI = 220V × 5A = 1100W
We know that energy consumed by the electric appliance = P × t
⇒ Energy consumed = 1100 W × 7200 s = 7920000 J = 7.92 × 106 J
Power Calculation:
The power (P) of an electrical device can be calculated using the formula:
P = 1 . V
Where:
» P is the power (in watts),
» I is the current (in amperes),
» V is the voltage (in volts).
Given:
I = 5 A (current)
V = 220 V (voltage)
substitute these values into the formula:
P = 5 A . 220V
P = 1100 W
So, the power of the motor is 1100W.
Energy Consumption Calculation:
The energy (E) consumed by the motor can be calculated using the formula:
E = P . t
where:
» E is the energy consumed (in watt-hours),
» P is the power (in watts),
» t is the time (in hours).
Given:
P = 1100 W (power)
t = 2h (time)
Substitute these values into the formula:
E = 1100 W . 2 h
E = 2200 Wh
So, the energy consumed by the motor in 2 hours is 2200 Wh or 2.2 kWh.