Reflection of light and spherical mirrors — practice questions

Question 1 · difficulty L1 · recall

The law of reflection states that the angle of reflection is

• A. equal to the angle of incidence
• B. twice the angle of incidence
• C. half the angle of incidence
• D. independent of incidence

Question 2 · difficulty L1 · understanding

The focal length f and radius of curvature R of a spherical mirror satisfy

• A. f=2R
• B. f=R/2
• C. f=R
• D. f=1/R

Question 3 · difficulty L2 · understanding

An object 'O' is placed at a distance of $$100 \mathrm{~cm}$$ in front of a concave mirror of radius of curvature $$200 \mathrm{~cm}$$ as shown in the figure. The object starts moving towards the mirror at a speed $$2 \mathrm{~cm} / \mathrm{s}$$. The position of the image from the mirror after $$10 \mathrm{~s}$$ will be at _________ $$\mathrm{cm}$$.

Question 4 · difficulty L2 · understanding

Distance between an object and three times magnified real image is 40 cm . The focal length of the mirror used is $\_\_\_\_$ cm .

• A. -20
• B. $-15 / 2$
• C. -10
• D. -15

Question 5 · difficulty L2 · understanding

In parallax method for the determination of focal length of a concave mirror, the object should always be placed:

• A. between the focus $(F)$ and the centre of curvature $(C)$ of the mirror ONLY
• B. between the pole $(P)$ and the focus $(F)$ of the concave mirror ONLY
• C. at any point beyond the focus $(F)$ of the mirror
• D. beyond the centre of the curvature $(C)$ of the mirror ONLY

Question 6 · difficulty L2 · understanding

A mirror is used to produce an image with magnification of $\frac{1}{4}$. If the distance between object and its image is 40 cm, then the focal length of the mirror is ________.

• A. 10 cm
• B. 12.7 cm
• C. 10.7 cm
• D. 15 cm

Question 7 · difficulty L2 · understanding

Two identical objects are placed in front of convex mirror and concave mirror having same radii of curvature of 12 cm , at same distance of 18 cm from the respective mirrors. The ratio of sizes of the images formed by convex mirror and by concave mirror is :

• A. 2
• B. $1 / 2$
• C. $1 / 3$
• D. 3

Question 8 · difficulty L2 · understanding

A concave mirror of focal length $f$ in air is dipped in a liquid of refractive index $\mu$. Its focal length in the liquid will be:

• A. $\mu f$
• B. $f$
• C. $\frac{f}{\mu}$
• D. $\frac{f}{(\mu-1)}$

Question 9 · difficulty L2 · understanding

A convex mirror of radius of curvature $$30 \mathrm{~cm}$$ forms an image that is half the size of the object. The object distance is :

• A. $$-$$45 cm
• B. $$-$$15 cm
• C. 45 cm
• D. 15 cm

Question 10 · difficulty L2 · understanding

When one light ray is reflected from a plane mirror with $$30^{\circ}$$ angle of reflection, the angle of deviation of the ray after reflection is :

• A. $$140^{\circ}$$
• B. $$130^{\circ}$$
• C. $$120^{\circ}$$
• D. $$110^{\circ}$$