1
NEET 2018
MCQ (Single Correct Answer)
+4
-1
Change Language
The refractive index of the material of a prism is $$\sqrt 2 $$ and the angle of the prism is 30°. One of the two refracting surfaces of the prism is made a mirror inwards, by silver coating. A beam of monochromatic light entering the prism from the other face will retrace its path (after reflection from the silvered surface) if its angle of incidence on the prism is
A
600
B
450
C
300
D
zero
2
NEET 2018
MCQ (Single Correct Answer)
+4
-1
Change Language
In Young’s double slit experiment the separation d between the slits is 2 mm, the wavelength $$\lambda $$ of the light used is 5896 $$\mathop A\limits^0 $$ and distance D between the screen and slits is 100 cm. It is found that the angular width of the fringes is 0.20o. To increase the fringe angular width to 0.21o (with same $$\lambda $$ and D) the separation between the slits needs to be changed to
A
1.9 mm
B
1.8 mm
C
2.1 mm
D
1.7 mm
3
NEET 2018
MCQ (Single Correct Answer)
+4
-1
Change Language
A pendulum is hung from the roof of a sufficiently high building and is moving freely to and fro like a simple harmonic oscillator. The acceleration of the bob of the pendulum is 20 m s–2 at a distance of 5 m from the mean position. The time period of oscillation is
A
2$$\pi $$ s
B
$$\pi $$ s
C
2 s
D
1 s
4
NEET 2018
MCQ (Single Correct Answer)
+4
-1
Change Language
Unpolarised light is incident from air on a plane surface of a material of refractive index $$\mu $$. At a particular angle of incidence i, it is found that the reflected and refracted rays are perpendicular to each other. Which of the following options is correct for this situation?
A
Reflected light is polarised with its electric vector parallel to the plane of incidence
B
Reflected light is polarised with its electric vector perpendicular to the plane of incidence
C
$$i = {\sin ^{ - 1}}\left( {{1 \over \mu }} \right)$$
D
i = tan-1$$\left( {{1 \over \mu }} \right)$$