1
NEET 2017
MCQ (Single Correct Answer)
+4
-1
Change Language
Young's double slit experiment is first performed in air and then in a medium other than air. It is found that 8th bright fringe in the medium lies where 5th dark fringe lies in air. The refractive index of the medium is nearly
A
1.59
B
1.69
C
1.78
D
1.25
2
NEET 2017
MCQ (Single Correct Answer)
+4
-1
Change Language
A beam of light from a source L is incident normally on a plane mirror fixed at a certain distance x from the source. The beam is reflected back as a spot on a scale placed just above the source L. When the mirror is rotated through a small angle $$\theta $$, the spot of the light is found to move through a distance y on the scale. The angle $$\theta $$ is given by
A
$${y \over x}$$
B
$${x \over {2y}}$$
C
$${x \over {y}}$$
D
$${y \over {2x}}$$
3
NEET 2017
MCQ (Single Correct Answer)
+4
-1
Change Language
A thin prism having refracting angle 10o is made of glass of refractive infex 1.42. This prism is combined with another thin prism of glass of refractive index 1.7. This combination producess dispersion without deviation. The refracting angle of second prism should be
A
6o
B
8o
C
10o
D
4o
4
NEET 2017
MCQ (More than One Correct Answer)
+4
-1
Change Language
The photoelectric threshold wavelength of silver is 3250 $$ \times $$ 10$$-$$10 m. The velocity of the electron ejected from a silver surface by ultraviolet light of wavelength 2536 $$ \times $$ 10$$-$$10 m is
{Given h = 4.14 $$ \times $$ 10$$-$$15 eV s and c = 3 $$ \times $$ 108 m s$$-$$1 ]
A
$$ \approx $$ 0.6 $$ \times $$ 106 m s$$-$$1
B
$$ \approx $$ 61 $$ \times $$ 103 m s$$-$$1
C
$$ \approx $$ 0.3 $$ \times $$ 106 m s$$-$$1
D
$$ \approx $$ 6 $$ \times $$ 105 m s$$-$$1