JEE Main Geometrical Optics Practice Questions With Solutions

A biconvex lens of refractive index 1.5 has a focal length of $20\mathrm{cm}$20 \textrm{ } cm in air. Its focal length when immersed in a liquid of refractive index 1.6 will be:

If the refractive index of the material of a prism is $\cot \left(\frac{A}{2}\right)$cot ⁡ \left(\right. \frac{A}{2} \left.\right), where $A$A is the angle of prism then the angle of minimum deviation will be

Identify the physical quantity that cannot be measured using spherometer :

A convex lens of focal length $40\mathrm{cm}$40 \textrm{ } cm forms an image of an extended source of light on a photoelectric cell. A current I is produced. The lens is replaced by another convex lens having the same diameter but focal length $20\mathrm{cm}$20 \textrm{ } cm. The photoelectric current now is :

A vessel of depth '$d$d' is half filled with oil of refractive index $n_1$n_{1} and the other half is filled with water of refractive index $n_2$n_{2}. The apparent depth of this vessel when viewed from above will be-

An ice cube has a bubble inside. When viewed from one side the apparent distance of the bubble is $12\mathrm{cm}$12 \textrm{ } cm. When viewed from the opposite side, the apparent distance of the bubble is observed as $4\mathrm{cm}$4 \textrm{ } cm. If the side of the ice cube is $24\mathrm{cm}$24 \textrm{ } cm, the refractive index of the ice cube is

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

The critical angle for a denser-rarer interface is ${45}^{\circ }$45^{\circ}. The speed of light in rarer medium is $3\times {10}^8\mathrm{m}/\mathrm{s}$3 \times 10^{8} \textrm{ } m / s. The speed of light in the denser medium is:

An object is placed at a distance of 12 cm in front of a plane mirror. The virtual and erect image is formed by the mirror. Now the mirror is moved by 4 cm towards the stationary object. The distance by which the position of image would be shifted, will be

In a reflecting telescope, a secondary mirror is used to: