Advertisements
Advertisements
प्रश्न
My mother was operating washing machine on Sunday morning. Suddenly, she saw a spark coming out of the electric board and the electric current in the house failed. An electrician was called to look into the matter. What should he have noticed.
उत्तर
- When electrician was called, he checked circuit and found that circuit catches fire due to short circuit.
- He observed that live wire and neutral wire came in direct contact which resulted in short circuit.
- Because short circuit resistance of the circuit becomes very small and hence huge amount of current flows through it.
- It ultimately produces a large amount of heat and raises the temperature. As a result circuit catches fire.
APPEARS IN
संबंधित प्रश्न
Three 2 V cells are connected in series and used as a battery in a circuit.
What is the p.d. at the terminals of the battery?
In which direction do electrons flow?
How many microamperes are there in 1 ampere?
Fill in the folloing blank with suitable words:
Current is measured in ............... using an ............... placed in ............... in a circuit.
What is an electric current?
Tick(✓) the correct choice in the following:
A three pin plug is connected to the lead for a 1 kW electric iron to be
used on a 250 V supply. Which of the following statements is not correct?
Two resistors P and Q of the same material and length but of different thickness are connected in parallel to a battery. The cross- sectional area of P is twice that of Q. What is the ratio of
(a) The resistance of P to the resistance of Q?
(b) The current in P to the current in Q?
What would be the danger involved in replacing a blown fuse with the one which would carry a large current?
Electrical appliances have voltage and power ratings as listed below. Which
has the larger working resistance?
Appliances | Voltage (V) | Power (W) |
(a) Washing machine | 250 | 3000 |
( b) Television | 240 | 160 |
(c)240 | 240 | 1500 |
( d) Hair curler | 250 | 20 |
( e) Car head lamp | 12 | 36 |
A wire is passed through a piece of cardboard as shown in fig .. An electric current flows vertically down the wire and then flows back up. The two sections of the write are observed to repel each other.
(a) Wi th the aid of a diagram, describe how you would plot the magnetic field lines on the card .
(b) Sketch the magnetic field patterns around both the sections of the wire. Use your sketch to explain why the two sections repel each other.
(c) The repulsive force between the two sections is small. What changes could be made to increase it?
An electric bulb is marked '100 W, 250 V'. What information does this convey?
Fill in the blank :
1 mA = ............................. A.
True or False – If False give the correct answer
The representation of the electric current is A
Which of the following represents voltage?
Electric current passes through a metallic conductor due to the movement of ______.
Find the odd one out.
What does the direction of current convey?