Electric Power

Q. Question 9
A certain household has consumed 250 units of energy during a month. How much energy is this in joules?

Q.

Question 27
Define watt. Express kilowatt in terms of joule per second. A 150 kg car engine develops 500 W for each kg. What force does it exert in moving the car at a speed of $20m{s}^{-1}$?

Q.

When starter of a car is switched on for 0.8s, 24C of charge passes through the coil of the motor. Calculate the current in the motor

1. 19.2 A

2. 30 A

3. 0.3 A

4. 3 A

Q.

An electric iron is rated $220\mathrm{V},1KW$. Under normal working conditions, find the amount of current that will flow through the element

Q. Question 4
Define average power.

Q.

Question 20
If an electric iron of 1200 W is used for 30 minutes every day, find electric energy consumed in the month of April.

Q. An electric bulb consumes $7.2\text{kJ}$ of electrical energy in $2$ minutes. What is the power of the bulb?

1. $40\text{W}$
2. $60\text{W}$
3. $50\text{W}$
4. $70\text{W}$

Q. An electrical appliance of $500W$ is used for $2$ hours per day. Calculate the energy consumed in a day.

1. 1

Q.

One electron volt is equal to

1. $1.6\times {10}^{-17}J$

2. $1.6\times {10}^{-19}J$

3. $1.6\times {10}^{-10}J$

4. $6.1\times {10}^{-19}J$

Q.

A sinusoidal voltage $V=200\sin \left(314t\right)$ is applied to a $10\Omega$ resistor. Find (i) RMS voltage, (ii) RMS current, and (iii) power dissipated as heat.

Q. The pressure of a gas filled in the bulb of constant volume gas thermometer at $0^{0}C$ and ${100}^{0}C$ are 28.6 cm and 36.6 cm of mercury respectively. The temperature of bulb at which pressure will be 35.00 cm of mercury will be:

1. ${80}^{0}C$
2. ${70}^{0}C$
3. ${55}^{0}C$
4. ${40}^{0}C$

Q.

Which uses more energy, a 250 W TV set in 1 h, or a 1200 W toaster in 10 minutes? [2 MARKS]

Q.

An electric bulb is rated 220 V and 100 W. When it is operated on 110 V, the power consumed will be:

1. 100 W

2. 75 W

3. 50 W

4. 25 W

Q. Safety fuse wire, used in electrical circuits, is made of a material having.

1. High melting point
2. High resistance
3. Low melting point
4. Low specific heat

Q.

If 100 J is the energy required per second for the appliance to run. What is the power consumed, if it operates at 220V.

1. Data insufficient

2. 22 W

3. 22000 W

4. 100 W

Q. A geyser is rated 1500 W, 250 V. This geyser is connected to 250 V mains. The energy consumed in 50 hours is:

1. $75kWh$
2. $50kWh$
3. $1500kWh$
4. $250kWh$

Q. A motor that pumps up water to a tank requires 10kW power. Its operating voltage is 220V. The only available resistor has a resistance of $11\Omega$. We know that we must use n such resistors in series and p such series resistor combinations in parallel. The values of n and p are respectively

1. 25 and 16
2. 11 and 25
3. 21 and 11
4. 16 and 25

Q. There are $5$ bulbs in a house written on them as $220volt$, $40$ watt. The bulb glow for $30$ days at the rate of $5$ hours per day. If the price of electric energy is Rs.$4$ per unit, calculate-
(i) equivalent resistance of the combination of bulbs
(ii) the number of electric units consumed.
(iii) the price of spent electric energy

Q. Which among the following is correct, where I = current, V = Potential difference, R = Resistance and P = electric power?

1. $P=I^v$
2. $P=\frac{V^2}{R}$
3. $V=P^{2}I$
4. $VI=P^2$

Q. D/dx of x to the power root x How to solve this??

Q.

The energy consumed when 5 kW power is dissipated for 2 hrs is equal to __ kJ.

Q. kilowatt-hour is the unit of ____.

1. potential difference
2. electric power
3. electric energy
4. charge

Q.

Define power. Give its unit.

Q. ___ is the range of voltage that must be(or can be) applied to household electrical appliances.

Q.

The rate of work done or electrical energy developed or consumed by a generator or appliance, is termed as electrical __.

Q.

When a tube-light rated 220V, 60W is connected across a potential of 220V for 22 sec then find the charge flowing in it.

1. 220 C

2. 6 C

3. 22 C

4. 4 C

Q. Re-write the following sentence according to the instructions given. Make other changes that may be necessary, but do not change the meaning of the sentence.
As soon as we lit the candle, the power supply was restored. (Begin: No sooner ....)

Q.

What is watt to

1. $A\Omega$

2. $A²\Omega$

3. $A\Omega ²$

4. $A\Omega ²s⁻¹$

Q. An electrical appliance of $500W$ is used for $2$ hours per day. Calculate the energy consumed in a day.

1. 1