Electricity — Science STD 10 — Question

A young man has to hold a book at arm's length to be able to read it clearly. The defect of vision is:

If the image formed is always virtual, the mirror can be:

1. Concave or convex.
2. Concave or plane.
3. Convex or plane.
4. Only convex.

Figure shows the magnetic field lines between the two faces A and B of two magnets.

An electric fuse works on the:

If three resistors 2 ohm, 3 ohm and 4 ohm are connected in series, then effective resistance in a circuit will be _______ ohm:

A perfecting reflecting mirror has an area of 1cm². Light energy is allowed to fall on it for an hour at the rate of 10cm^-2. The force that acts on the mirror is:

The force experienced by a current-carrying conductor placed in a magnetic field is the largest when the angle between the conductor and the magnetic field is:

1. 45°
2. 60°
3. 90°
4. 180°

A person cannot see the distant objects clearly (though he can see the nearby objects clearly). He is suffering from the defect of vision called:

1. Cataract.
2. Hypermetropia.
3. Myopia.
4. Presbyopia.

The lamps in a house hold circuit are connected in parallel because:

A virtual, erect and magnified image of an object is to be obtained with a convex lens. For this purpose,the object should be placed:

1. Between 2F and infinity.
2. Between F and optical centre.
3. Between F and 2F.
4. At F.