Precautions While Using Electricity

Q. What is the difference between overloading and short circuiting.
please explain in detail.

Q. ntTwo magnets are held together in a vibration magnetometer and are allowed to oscillate in the earths magnetic field. With like poles of magnets together, 12 oscillations per minute are made but for unlike poles together only 4 oscillations per minute are executed.The ratio of their magnetic moments isn nt1-1:3n nt2-3:1n nt3-3:5n nt4-5:4n

Q.

Choose only incorrect statement out of the following

1. In our houses, we receive AC electric power at 200V and 50 Hz.

2. Electric power as an AC can be easily transmitted over long distances without much loss of energy.

3. In India, the AC changes direction after every 1/50 second.

4. In India, the AC changes direction after every 1/100 second.

Q. Assertion : If the bob of a simple pendulum is kept in horizontal electric field then its period of oscillations will be unchanged Reason: If the bob is charged and kept in electric field the time period will decrease

Q. From a supply of identical capacitors rated 8uF , 250V the minimum number of capacitors required to form a composite 16 uF, 1000V

Q. If two points are at different potentials , then the current will flow till the time both the points reach the same potential( without a battery).
Now the question is that - If we connect the switch in the neutral wire, when the switch is off, the appliance is connected to the higher potential through the live wire ( which was not disconnected), the current flows through the live wire to the appliance . If we now touch the appliance, we will get shock because the appliance was at higher potential and our body was at a lower potential, thus current moved Through our body. But even if we wear rubber shoes ( or some insulation between our body and earth is there) , we should get shock because the only change that happens now is that the current doesn't reach ground. But it will flow TO our body (lower potential ) from the live wire (higher potential) even if there is not a return path for current ( not a complete circuit). Why is this not true ?

Q.

List the safety measures that should be taken while handling electricity.

Q.

What do we mean by saying

"Frequency of AC current is 50hz for Indian houhold"?

Q.

We will receive an electric shock if we touch

1. a live wire

2. an earth wire

3. a neutral wire

4. any of the above

Q. How many bulbs of resistance 6ohms should be joined in parallel to draw a current of 2 amperes from a battery of 3 volts

Q. ntThe length of a magnet is large compared to its width and breadth.The time period of its oscillation in a vibration magnetometer is 2 sec.The magnet is cut along its length into three equal parts.These parts are then placed on each other with their like poles together.The time period of this combination will ben nta)2 secn ntb)2/3 secn ntc)2sqrt3 secn ntd)2/sqrt3 secn

Q.

where is series and parallel combination used?

Q.

Will we get earth if we were rubber slippers?why?

Q. I have two resistors of R1 and R2 connected across voltage source of voltage V .now why dont all the voltage drop V does not drop across R1.?

Q. List three factors which can cause overloading of domestic electric circuits

Q.

What is a three-core flexible wire?

Q.

Draw a labelled diagram with the necessary switch, regulator, etc. to connect a bulb and a fan with the mains. In what arrangement are they connected to the mains : series or parallel?

Q. In an electrical circuit, ammeter is always connected in ____ with the load or the circuit.

1. parallel
2. neither parallel nor series
3. parallel or series
4. series

Q.

Why is it necessary to have an earth wire installed in a power circuit, but not in a lighting circuit ?

Q.

What is the difference between overloading and short circuit in domestic electri circuit?

Q.

What do you mean by short circuiting?

Q.

(a) A switch is not touched with wet hands while putting it on or off. Give a reason for your answer.

(b) Name the wire to which a switch is connected.

Q.

Write five safety rules or precautions while handling any electrical component or appliance.

Q.

Give one precaution that should be taken while handling switches.

Q.

How can you avoid overloading?

Q.

State few safety precautions that should be taken while using electricity.

Q. Write any two point difference between overloading and short circuiting.

Q. Birds do not feel electric shock while sitting on current carrying uninsulated wires because ............. .

1. The feathers of birds act as insulator and hence the current does not pass through them
2. The resistance offered by the body of birds is very high
3. The current does not pass through the body as the claws of birds are non-conducting
4. The potential difference between the two claws of the birds is very small

Q.

What consequences will follow, if a switch is placed in a neutral wire?

Q. You told in topic Domestic Electric Circuit that a plug of 3 pins consists of Earth pin, Live pin and Neutral pin. But for some plugs having only 2 pins don't have Earth pin or have Earth pin?