1
JEE Main 2024 (Online) 8th April Morning Shift
+4
-1

Critical angle of incidence for a pair of optical media is $$45^{\circ}$$. The refractive indices of first and second media are in the ratio:

A
$$1: 2$$
B
$$1: \sqrt{2}$$
C
$$2: 1$$
D
$$\sqrt{2}: 1$$
2
JEE Main 2024 (Online) 6th April Evening Shift
+4
-1

For the thin convex lens, the radii of curvature are at $$15 \mathrm{~cm}$$ and $$30 \mathrm{~cm}$$ respectively. The focal length the lens is $$20 \mathrm{~cm}$$. The refractive index of the material is :

A
1.2
B
1.5
C
1.4
D
1.8
3
JEE Main 2024 (Online) 4th April Morning Shift
+4
-1

An effective power of a combination of 5 identical convex lenses which are kept in contact along the principal axis is $$25 \mathrm{D}$$. Focal length of each of the convex lens is:

A
50 cm
B
20 cm
C
25 cm
D
500 cm
4
JEE Main 2024 (Online) 4th April Morning Shift
+4
-1

In an experiment to measure focal length ($$f$$) of convex lens, the least counts of the measuring scales for the position of object (u) and for the position of image (v) are $$\Delta u$$ and $$\Delta v$$, respectively. The error in the measurement of the focal length of the convex lens will be:

A
$$2 f\left[\frac{\Delta \mathrm{u}}{\mathrm{u}}+\frac{\Delta \mathrm{v}}{\mathrm{v}}\right]$$
B
$$f\left[\frac{\Delta \mathrm{u}}{\mathrm{u}}+\frac{\Delta \mathrm{v}}{\mathrm{v}}\right]$$
C
$$f^2\left[\frac{\Delta \mathrm{u}}{\mathrm{u}^2}+\frac{\Delta \mathrm{v}}{\mathrm{v}^2}\right]$$
D
$$\frac{\Delta \mathrm{u}}{\mathrm{u}}+\frac{\Delta \mathrm{v}}{\mathrm{v}}$$
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