Electricity — Science STD 10 — Question

Identify the incorrect statement: Magnetic field lines due to a circular coil is:

Magnitude of the magnetic force experienced by a current carrying conductor in a uniform magnetic field is maximum when the magnetic field and current direction are:

Choose the incorrect statement from the following regarding magnetic lines of field:

The back face of a circular loop of wire is found to be south magnetic pole. The direction of current in this face of the circular loop of wire will be:

1. Towards south.
2. Clockwise.
3. Anticlockwise.
4. Towards north.

A current of 1A is drawn by a filament of an electric bulb. Number of electrons passing through a cross section of the filament in 16 seconds would be roughly:

1. 10²⁰
2. 10¹⁶
3. 10¹⁸
4. 10²³

With age Near point and Far point receeds due to:
A: Weakening of ciliary muscles.
B: Reducing ability to change the focal length.

Light travelling from a denser medium to a rarer medium along a normal to the boundary:

If a spherical lens has a power of, -0.25D, the focal length of this lens will be:

1. -4cm
2. -400mm
3. -4m
4. -40cm