Transformer

Q.

What is the function of an earth wire? Why is it necessary to earth metallic appliances?

Q.

Why is iron used in transformers?

Q.

Write the working of three types of wires used in domestic circuiting.

Q.

Explain the electric circuit and draw a simple electric circuit

Q.

A step-up transformer operates at 200 volt line. The ratio of primary to secondary turns is 1:5. The output voltage in secondary coil is

1. 0.1 V
2. 70 V
3. 1000 V
4. 2 V

Q.

A transformer has $250$ primary turns and $500$ secondary turns. If $200V$ electric potential is applied to the primary resulting in a current of $5mA$, find the secondary voltage and current.

Q.

What is the most common bias circuit?

Q.

In a transformer, the output current and voltage are respectively $4A$ and $20V$. If the ratio of the number of turns in the primary to secondary is $2:1$ what is the input current and voltage?

Q. Sort the following electric components in the correct order from the mainline to an appliance of a household.

1. kWh meter
2. Main fuse
3. ELCB or MCB
4. Switchboard
5. Home appliance

Q. Fuse wire must have melting point than the circuit wire.

1. higher
2. lower
3. equitable

Q. A transformer is a device which can change the of the induced alternating e.m.f.

1. direction
2. magnitude
3. order

Q.

The primary coil of a transformer contains 100 turns; the secondary has 200 turns. The primary coil is connected to a DC source that supplies a constant voltage of 1.5 volt. What is the voltage measured across the secondary coil?

1. 3 volt

2. 0.75 volt

3. 0 volt

4. 1.5 volt

Q. A particular transformer is designed to turn 12 V into 240 V and a maximum current of 5 A. What should be the turn ratio for the step-down transformer used?

1. 240: 5
2. 5: 240
3. 20: 1
4. 1: 20

Q. Three resistances are connected to form the sides of triangle ABC. The resistance of the side AB is 40 ohm of the side BC is 60 ohm and its side
CA is 100 ohm. The effective resistance between points A and B is:

1. $32\Omega$
2. $16\Omega$
3. $\frac{80}{3}\Omega$
4. $20\Omega$