1
JEE Main 2021 (Online) 27th July Morning Shift
+4
-1
The relative permittivity of distilled water is 81. The velocity of light in it will be :

(Given $$\mu$$r = 1)
A
4.33 $$\times$$ 107 m/s
B
2.33 $$\times$$ 107 m/s
C
3.33 $$\times$$ 107 m/s
D
5.33 $$\times$$ 107 m/s
2
JEE Main 2021 (Online) 27th July Morning Shift
+4
-1
In Young's double slit experiment, if the source of light changes from orange to blue then :
A
the central bright fringe will become a dark fringe.
B
the distance between consecutive fringes will decrease.
C
the distance between consecutive fringes will increases.
D
the intensity of the minima will increase.
3
JEE Main 2021 (Online) 25th July Evening Shift
+4
-1
A prism of refractive index $$\mu$$ and angle of prism A is placed in the position of minimum angle of deviation. If minimum angle of deviation is also A, then in terms of refractive index
A
$$2{\cos ^{ - 1}}\left( {{\mu \over 2}} \right)$$
B
$${\sin ^{ - 1}}\left( {{\mu \over 2}} \right)$$
C
$${\sin ^{ - 1}}\left( {\sqrt {{{\mu - 1} \over 2}} } \right)$$
D
$${\cos ^{ - 1}}\left( {{\mu \over 2}} \right)$$
4
JEE Main 2021 (Online) 25th July Evening Shift
+4
-1
A ray of light entering from air into a denser medium of refractive index $${4 \over 3}$$, as shown in figure. The light ray suffers total internal reflection at the adjacent surface as shown. The maximum value of angle $$\theta$$ should be equal to :

A
$${\sin ^{ - 1}}{{\sqrt 7 } \over 3}$$
B
$${\sin ^{ - 1}}{{\sqrt 5 } \over 4}$$
C
$${\sin ^{ - 1}}{{\sqrt 7 } \over 4}$$
D
$${\sin ^{ - 1}}{{\sqrt 5 } \over 3}$$
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