Magnetism And Matter — Physics STD 12 Science — Question

A toroid has number of turns per unit length n, current i, then the magnetic field is

(a)

(b)

(c)

(d) None of these

1 electron volt = __________ J.

Matter waves are:

A person A can clearly see objects between 25cm and 200cm. Which of the following may represent the range of clear vision for a person B having muscles stronger than A, but all other parameters of eye identical to that of A?

1. 25cm to 200cm.
2. 18cm to 200cm.
3. 25cm to 300cm.
4. 18cm to 300cm.

A metallic sheet is inserted between the plates of a parallel plate capacitor. The capacitance of the capacitor

(a) Increases

(b) Is independent of the position of the sheet

(c) Is maximum when the metal sheet in the middle

(d) a, b

If a dielectric introduced between the plates of a parallel plate condenser, then which of the following is possible:

Figure shows a charge q placed at the centre of a hemisphere. A second charge Q is placed at one of the positions A, B, C and D. In which position(s) of this second charge, the flux of the electric field through the hemisphere remains unchanged?

An object is at a distance of 0.5 m in front of a plane mirror. Distance between the object and image is

(a) 0.5 m

(b) 1 m

(c) 0.25 m

(d) 1.5 m

A photo cell is receiving light from a source placed at a distance of 1 m. If the same source is to be placed at a distance of 2 m, then the ejected electron

(a) Moves with one-fourth energy as that of the initial energy

(b) Moves with one-fourth of momentum as that of the initial momentum

(c) Will be half in number

(d) Will be one-fourth in number

Electroscope is used: