A soldier directs a laser beam on an enemy by reflecting the beam from a mirror. If the mirror is rotated by an angle $\mathrm{\theta }$, by what angle will be reflected beam rotate?

1.  $\mathrm{\theta }$/2

2.  $\mathrm{\theta }$

3.  2$\mathrm{\theta }$

4.  None of these

When an object is at a distance of ${\mathrm{\mu }}_1 \mathrm{and} {\mathrm{\mu }}_2$ from the poles of a concave mirror, images of the same size are formed. The focal length of the mirror is:

1.  ${\mu }_1 + {\mu }_2$

2.  ${\mu }_1 - {\mu }_2$

3.  $\frac{{\mu }_1 + {\mu }_2}{2}$
4.  $\frac{{\mu }_1 - {\mu }_2}{2}$

A given ray of light suffers minimum deviation in an equilateral prism P. Additional prism Q and R of identical shape and of the same material as P is now added as shown in the figure. The ray will now suffer:

1.  greater deviations 

2.  no deviation

3.  same deviation as before 

4.  total internal reflection

For a spherical mirror, the graph of 1/v versus 1/u is given by:

1.  

2.  

3.  

4.  

The focal length of the objective and the eyepiece of a microscope are 4 mm and 25 mm respectively. If the final image is formed at infinity and the length of the tube is 16 cm, then the magnifying power of the microscope will be:

1.  -327.5

2.  -3.75

3.  3.3275

4.  32.75

The figure shows a concavo-convex lens. What is the condition on the refractive indices so that the lens is diverging?

1. $2{\mu }_3<{\mu }_1+{\mu }_2$

2. $2{\mu }_3>{\mu }_1+{\mu }_2$

3. ${\mu }_3>2({\mu }_1-{\mu }_2)$

4. None of these

Statement I: If a source of light is placed in front of the rough wall its image is not seen.

Statement II: The wall does not reflect light.

1. Statement I is true, statement 2 is true; statement 2 is the correct explanation for statement I

2. Statement 1 is true, statement 2 is true; statement 2 is not the correct explanation for statement 1

3. Statement 1 is true, statement 2 is false.

4. Statement 1 is false, statement 2 is true

A thin prism having refracting angle 10⁰ is made of glass of refractive index 1.42. This prism is combined with another thin prism of a glass of refractive index 1.7. This combination produces dispersion without deviation. The refracting angle of the second prism should be:-

1. $6^o$

2. $8^o$

3. ${10}^o$

4. $4^o$

In an astronomical telescope in normal adjustment, a straight line of length L is drawn on inside part of the objective lens. The eye-piece forms a real image of this line. The length of this image is I. The magnification of the telescope is :

1. $\frac{L}{I}+1$

2. $\frac{L}{I}-1$

3. $\frac{L+1}{I-1}$

4. $\frac{L}{I}$

A beam of light consisting of red, green, and blue colors is incident on a right-angled prism. The refractive index of the material of the prism for the red, green, and blue wavelengths is 1.39, 1.44, and 1.47 respectively. 
 
The prism will :

1. separate the blue color part from the red and green color

2. separate all the three colors from one another

3. Not separate the three colors at all 

4. Separate the red color part from the green and blue colors