Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

5 amperes of current is passed through a metallic conductor. The charge flowing in one minute in coulombs will be

(a) 5

(b) 12

(c) 1/12

(d) 300

One can define ...A... of a place as the vertical plane which passes through the imaginary line joining the magnetic North and the South–poles.

Here, A refers to.

A beam of fast moving alpha particles were directed towards a thin film of gold. The parts  and  of the transmitted and reflected beams corresponding to the incident parts A, B and C of the beam, are shown in the adjoining diagram. The number of alpha particles in

(a)  will be minimum and in  maximum	(b)  will be maximum and in  minimum
(c)  will be minimum and in  maximum	(d)  will be minimum and in  maximum

Mark out the correct options.

A transistor is used as an amplifier in CB mode with a load resistance of 5 k W the current gain of amplifier is 0.98 and the input resistance is 70 W, the voltage gain and power gain respectively are

(a) 70, 68.6

(b) 80, 75.6

(c) 60, 66.6

(d) 90, 96.6

In series combination of resistances:

The focal length of the field lens (which is an achromatic combination of two lenses) of telescope is 90 cm. The dispersive powers of the two lenses in the combination are 0.024 and 0.036. The focal lengths of two lenses are

(a) 30 cm and 60 cm	(b) 30 cm and – 45 cm
(c) 45 cm and 90 cm	(d) 15 cm and 45 cm

 Identify the electromagnetic wave which is also known as heatwaves.

Mark the correct options:

1. If the far point goes ahead, the power of the divergent lens should be reduced.
2. If the near point goes ahead, the power of the convergent lens should be reduced.
3. If the far point is 1 m away from the eye, divergent lens should be used.
4. If the near point is 1 m away from the eye, divergent lens should be used.

The SI unit of electric field is: