Power

Q. If a $1200W$ electric iron is used daily for $30$ minutes, calculate the electricity consumed for the month of june.

1. $18kWhr$
2. $21kWhr$
3. $24kWhr$
4. $15kWhr$

Q.

The SI unit of power is

1. Watt

2. Joule per second

3. Watt-hour

4. Kilowatt-hour

Q.

The power of a motor is 40kW.At what speed can the motor raise a load of 20, 000 N?

Q.

How many watts equal one horse power ?

Q. Question 3
A lamp consumes 1000 J of electrical energy in 10 s. What is its power?

Q. Power and energy are scalar quantity or vector quantity?

Q. If a bulb of 50 watts is used for 8 hours a day . How many unit it uses. How to find it?
what is the formula for it?

Q.

Is power scalar or vector?

Q.

An electric bulb of 40watt is used 50 days at 5 hrs perday find the unit of energy consumed by bulband cost of using electricity at the rate of 10 rupees per unit

Q.

Five electric fans of 120 watts each are used for 4 hours. Calculate the electrical energy consumed in kilowatt hours.

Q. A car of mass 1000 kg accelerated uniformly from rest to a velocity of 54 km/h in 5 s. Find the average power of the engine during this period.

1. $22.5kW$
2. $45kW$
3. $60kW$
4. $90kW$

Q. Full form of kwh

Q. What do you mean by 1hp

Q.

Define the term 'Watt'.

Q.

A horse exerts a pull on a cart of 300 N so that the house-cart system moves with a uniform speed 18 km/h on a level road. Calculate the power developed by the horse in watt and also find its equivalent in horsepower.

Q.

6.7 into 10 power Minus 11into six into 10 power 24 KG into 7.4 into 10 power 22 KG by 3.84 into 10 power 8 m whole square

Q. An electric bulb consumes 7.2 kJ of electrical energy in 2 minutes. What is the power of the electric bulb?

1. $40W$
2. $60W$
3. $50W$
4. $70W$

Q.

An electric heater uses 600 kJ of electrical energy in 5 minutes. Calculate its power rating.

Q.

What is the power of a pump which takes 10 seconds to lift 100 kg of water to a water tank situated at a height of 20 m? Take $g=10m{s}^{-2}$

1. $5KW$

2. $4KW$

3. $3KW$

4. $2KW$

Q. Calculate the kinetic energy of a car of mass 750 kg moving with a velocity of 54 km per hour. Find the new kinetic energy of the car if a passenger of mass 50 kg sits in the car.

Q.

watt-second is the unit of power.

1. True
2. False

Q.

One unit of electric energy is equal to

1. One kilowatt-hour

2. One watt-hour

3. $100$ joules

4. None of the above

Q.

(a) What is the meaning of the symbol kWh ? What quantity does it represent ?

(b) How much electric energy in kWh is consumed by an electrical appliance of 1000 watts when it is switched on for 60 minutes ?

Q.

How much energy does a 100 W electric bulb transfer in 1 minute ?

(a) 100 J

(b) 600 J

(c) 3600 J

(d) 6000 J

Q.

A man whose mass is 50 kg climbs up 30 steps of the stairs in 30 seconds. If each step is 20 cm high, calculate the power used in climbing the stairs.

Q.

Which one of the following is not the unit of energy ?

(a) joule

(b) newton-metre

(c) kilowatt

(d) kilowatt-hour

Q.

Calculate the work done A car of weight $20000\mathrm{N}$ climbs up a hill at $8\mathrm{m}/\mathrm{s}$ speed. Gaining a height of$120\mathrm{m}$ in $100\mathrm{s}$.

Q. A body of mass 2 kg starts from rest and moves with uniform acceleration. It acquires a velocity of 20 m/s in 4 seconds.The power exerted on the body in 2 seconds is

1. $500Watts$
2. $100Watts$
3. $50Watts$
4. $200Watts$

Q.

Time taken for 60W electric bulb to consume 3000 J energy is 50 seconds

1. False

2. True

Q. What do you mean by commercial unit of power? write its unit.