### JEE Mains Previous Years Questions with Solutions

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1

### AIEEE 2003

To get three images of a single object, one should have two plane mirrors at an angle of
A
${60^ \circ }$
B
${90^ \circ }$
C
${120^ \circ }$
D
${30^ \circ }$

## Explanation

When $\theta = {90^ \circ }$ then ${{360} \over \theta } = {{360} \over {90}} = 4$

is an even number. The number of images formed is given by

$n = {{360} \over \theta } - 1 = {{360} \over {90}} - 1 = 4 - 1 = 3$
2

### AIEEE 2003

The image formed by an objective of a compound microscope is
A
virtual and diminished
B
real an diminished
C
real and enlarged
D
virtual and enlarged

## Explanation

A real, inverted and enlarged image of the object is formed by the objective lens of a compound microscope.
3

### AIEEE 2003

To demonstrate the phenomenon of interference, we require two sources which emit radiation
A
of nearly the same frequency
B
of the same frequency
C
of different wavelengths
D
of the same frequency and having a definite phase relationship

## Explanation

For the phenomenon of interference we require two sources of light of same frequency and having a definite phase relationship (a phase relationship that does not change with time)
4

### AIEEE 2002

which of the following is used in optical fibres?
A
total internal reflection
B
scattering
C
diffracttion
D
refraction

## Explanation

In an optical fibre, light is sent through the fibre without any loss by the phenomenon of total internal reflection as shown in the figure.