Magnetic Effects of Electric Current — Science STD 10 — Question

A ray of light strikes a plane mirror PQ at an angle of incidence of 30°, is reflected from the plane mirror and then strikes a second plane mirror QR placed at right angles to the first mirror. The angle of reflection at the second mirror is:

The least distance of distinct vision for an eye lens is caused by the action of the:

The shape of eye-ball is nearly _________________

At a hydro power plant:

1. Kinetic energy possessed by stored water is converted into electrical energy.
2. Electrical is extracted from water.
3. Water is converted into steam to turn turbines and produce electricity.
4. Potential energy possessed by stored water is converted into electricity.

One MeV of nuclear energy is equivalent to:

1. 1.6 × 10⁻¹³J.
2. 1.6 × 10⁻¹⁹J.
3. 1.6 × 10⁻¹⁶J.
4. 1.6 × 10⁻¹⁵J.

The north-south polarities of an electromagnet can be found easily by using:

The most important safety method used for protecting home appliances from short circuiting or overloading is:

1. Earthing.
2. Use of fuse.
3. Use of stabilizers.
4. Use of electric meter.

To obtain a magnification of, -2 with a convex lens of focal length 10cm, the object should be placed:

1. Between 5cm and 10cm.
2. Between 10cm and 20cm.
3. At 20cm.
4. Beyond 20cm.

If a magnification of, -1 is to be obtained by using a converging lens of focal length 12cm, then the object must be placed:

1. Within 12cm.
2. At 24cm.
3. At 6cm.
4. Beyond 24cm.

The north pole of a long bar magnet was pushed slowly into a short solenoid connected to a galvanometer. The magnet was held stationary for a few seconds with the north pole in the middle of the solenoid and then withdrawn rapidly. The maximum deflection of the galvanometer was observed when the magnet was: