10 QA on Diffraction of light | Learn Physics

10 Question-Answer on Diffraction of light

1.       What will be the angle of diffraction for first secondary maximum due to diffraction at a single slit of width 0.55 mm, using light of wavelength 550 nm.

(a)    00.0015 rad

(b)   0.00015 rad

(c)    0.003 rad

(d)   0.0010 rad.

Ans: (a)

2.       The bending of beam of light around corners of obstacles is called:

(a)    Reflection

(b)   Diffraction

(c)    Refraction

(d)   Interference

Ans: (b)

3.        To observe diffraction, the size of an aperture

(a)    Should be of the same order as wavelength

(b)   Should be much larger than the wavelength

(c)    Have no relation to wavelength

(d)   Should be exactly λ/2.

Ans: (a)

4.       A parallel beam of monochromatic light is incident normally on a slit. The diffraction pattern is observed on a screen placed at the focal plane of a convex lens. If the slit width is increased, the central maximum of the diffraction pattern will:

(a)    Become broader and fainter

(b)   Become broader and brighter

(c)    Become narrower and fainter

(d)   Become narrower and brighter

Ans: (d)

5.       If the red light is replaced by blue light illuminating the object in a microscope, the resolving power of the microscope:

(a)    Decreases

(b)   Increases

(c)    Gets halved

(d)   Remains unchanged

Ans: ( b)

6.       Which of the following undergo maximum diffraction?

(a)    Alpha rays

(b)   Gamma rays

(c)    Radio waves

(d)   Light waves

Ans: (c)

7.       Which of the following waves are diffracted by an obstacle of size 1 cm?

(a)    Light waves

(b)   Sound waves

(c)    Ultra-sonic waves

(d)   X-rays.

Ans: (c)

8.       The condition for observing Fraunhofer diffraction from a single slit is that the light wave front incident on the slit  should be:

(a)    Spherical

(b)   Cylindrical

(c)    Plane

(d)   Elliptical

Ans:(c)

9.       Diffraction pattern is obtained using red light. What will happen if it is replaced by violet light?

(a)    Bands will disappear

(b)   Bands will become narrow

(c)    Bands will get spaced apart

(d)   Bands will remain unchanged.

Ans: ( b)

10.   In a diffraction pattern,   the width of  any fring is:

(a)    Directly proportional to slit width

(b)   inversely proportional to slit width

(c)    has  no  dependence to slit width

(d)   all  are true

Diffraction of light

1.       What will be the angle of diffraction for first secondary maximum due to diffraction at a single slit of width 0.55 mm, using light of wavelength 550 nm.

(a)    00.0015 rad

(b)   0.00015 rad

(c)    0.003 rad

(d)   0.0010 rad.

Ans: (a)

2.       The bending of beam of light around corners of obstacles is called:

(a)    Reflection

(b)   Diffraction

(c)    Refraction

(d)   Interference

Ans: (b)

3.        To observe diffraction, the size of an aperture

(a)    Should be of the same order as wavelength

(b)   Should be much larger than the wavelength

(c)    Have no relation to wavelength

(d)   Should be exactly λ/2.

Ans: (a)

4.       A parallel beam of monochromatic light is incident normally on a slit. The diffraction pattern is observed on a screen placed at the focal plane of a convex lens. If the slit width is increased, the central maximum of the diffraction pattern will:

(a)    Become broader and fainter

(b)   Become broader and brighter

(c)    Become narrower and fainter

(d)   Become narrower and brighter

Ans: (d)

5.       If the red light is replaced by blue light illuminating the object in a microscope, the resolving power of the microscope:

(a)    Decreases

(b)   Increases

(c)    Gets halved

(d)   Remains unchanged

Ans: ( b)

6.       Which of the following undergo maximum diffraction?

(a)    Alpha rays

(b)   Gamma rays

(c)    Radio waves

(d)   Light waves

Ans: (c)

7.       Which of the following waves are diffracted by an obstacle of size 1 cm?

(a)    Light waves

(b)   Sound waves

(c)    Ultra-sonic waves

(d)   X-rays.

Ans: (c)

8.       The condition for observing Fraunhofer diffraction from a single slit is that the light wave front incident on the slit  should be:

(a)    Spherical

(b)   Cylindrical

(c)    Plane

(d)   Elliptical

Ans:(c)

9.       Diffraction pattern is obtained using red light. What will happen if it is replaced by violet light?

(a)    Bands will disappear

(b)   Bands will become narrow

(c)    Bands will get spaced apart

(d)   Bands will remain unchanged.

Ans: ( b)

10.   In a diffraction pattern,   the width of  any fring is:

(a)    Directly proportional to slit width

(b)   inversely proportional to slit width

(c)    has  no  dependence to slit width

(d)   all  are true