1
JEE Main 2023 (Online) 8th April Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

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

A
make chromatic aberration zero
B
remove spherical aberration
C
reduce the problem of mechanical support
D
move the eyepiece outside the telescopic tube
2
JEE Main 2023 (Online) 6th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R

Assertion A: The phase difference of two light waves change if they travel through different media having same thickness, but different indices of refraction.

Reason R: The wavelengths of waves are different in different media.

In the light of the above statements, choose the most appropriate answer from the options given below

A
Both A and R are correct but R is NOT the correct explanation of A
B
A is correct but R is not correct
C
A is not correct but R is correct
D
Both A and R are correct and R is the correct explanation of A
3
JEE Main 2023 (Online) 6th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

A 2 meter long scale with least count of $$0.2 \mathrm{~cm}$$ is used to measure the locations of objects on an optical bench. While measuring the focal length of a convex lens, the object pin and the convex lens are placed at $$80 \mathrm{~cm}$$ mark and $$1 \mathrm{~m}$$ mark, respectively. The image of the object pin on the other side of lens coincides with image pin that is kept at $$180 \mathrm{~cm}$$ mark. The $$\%$$ error in the estimation of focal length is:

A
1.70
B
0.51
C
1.02
D
0.85
4
JEE Main 2023 (Online) 6th April Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

A monochromatic light wave with wavelength $$\lambda_{1}$$ and frequency $$v_{1}$$ in air enters another medium. If the angle of incidence and angle of refraction at the interface are $$45^{\circ}$$ and $$30^{\circ}$$ respectively, then the wavelength $$\lambda_{2}$$ and frequency $$v_{2}$$ of the refracted wave are:

A
$$\lambda_{2}=\lambda_{1}, v_{2}=\frac{1}{\sqrt{2}} v_{1}$$
B
$$\lambda_{2}=\lambda_{1}, v_{2}=\sqrt{2} v_{1}$$
C
$$\lambda_{2}=\sqrt{2} \lambda_{1}, v_{2}=v_{1}$$
D
$$\lambda_{2}=\frac{1}{\sqrt{2}} \lambda_{1}, v_{2}=v_{1}$$
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