JEE Main 2017 (Online) 9th April Morning Slot | Ray & Wave Optics Question 206 | Physics

JEE Main 2017 (Online) 9th April Morning Slot

MCQ (Single Correct Answer)

-1

In an experiment a convex lens of focal length 15 cm is placed coaxially on an optical bench in front of a convex mirror at a distance of 5 cm from it. It is found that an object and its image coincide, if the object is placed at a distance of 20 cm from the lens. The focal length of the convex mirror is :

27.5 cm

20.0 cm

25.0 cm

30.5 cm

JEE Main 2017 (Online) 9th April Morning Slot

MCQ (Single Correct Answer)

-1

A single slit of width 0.1 mm is illuminated by a parallel beam of light of wavelength 6000 $$\mathop A\limits^ \circ $$ and diffraction bands are observed on a screen 0.5 m from the slit. The distance of the third dark band from the central bright band is :

3 mm

9 mm

4.5 mm

1.5 mm

JEE Main 2017 (Online) 8th April Morning Slot

MCQ (Single Correct Answer)

-1

Let the refractive index of a denser medium with respect to a rarer medium be n₁₂ and its critical angle be θ_C . At an angle of incidence A when light is travelling from denser medium to rarer medium, a part of the light is reflected and the rest is refracted and the angle between reflected and refracted rays is 90^o. Angle A is given by :

$${1 \over {{{\cos }^{ - 1}}\left( {\sin {\theta _C}} \right)}}$$

$${1 \over {{{\tan }^{ - 1}}\left( {\sin {\theta _C}} \right)}}$$

$${\cos ^{ - 1}}\,\left( {\sin {\theta _C}} \right)$$

$${\tan ^{ - 1}}\,\left( {\sin {\theta _C}} \right)$$

JEE Main 2017 (Online) 8th April Morning Slot

MCQ (Single Correct Answer)

-1

A single slit of width b is illuminated by a coherent monochromatic light of wavelength $$\lambda $$. If the second and fourthminima in the diffraction pattern at a distance 1 m from the slit are at 3 cm and 6 cm respectively from the central maximum, what is the width of the central maximum ? (i.e. distance between first minimum on either side of the central maximum)

1.5 cm

3.0 cm

4.5 cm

6.0 cm

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