JEE Main 2024 (Online) 27th January Morning Shift | Geometrical Optics Question 20 | Physics

A convex lens of focal length $$40 \mathrm{~cm}$$ 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 $$20 \mathrm{~cm}$$. The photoelectric current now is :

$$\mathrm{\frac{I}{2}}$$

4 I

2 I

JEE Main 2023 (Online) 13th April Morning Shift

MCQ (Single Correct Answer)

-1

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

$$\frac{2 d\left(n_{1}+n_{2}\right)}{n_{1} n_{2}}$$

$$\frac{d\left(n_{1}+n_{2}\right)}{2 n_{1} n_{2}}$$

$$\frac{d n_{1} n_{2}}{2\left(n_{1}+n_{2}\right)}$$

$$\frac{d n_{1} n_{2}}{\left(n_{1}+n_{2}\right)}$$

JEE Main 2023 (Online) 12th April Morning Shift

MCQ (Single Correct Answer)

-1

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

$$\frac{3}{2}$$

$$\frac{4}{3}$$

$$\frac{2}{3}$$

$$\frac{6}{5}$$

JEE Main 2023 (Online) 11th April Evening Shift

MCQ (Single Correct Answer)

-1

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 :

$$140^{\circ}$$

$$130^{\circ}$$

$$120^{\circ}$$

$$110^{\circ}$$