Light is incident normally on a diffraction grating through which the first diffraction is seen at 32°. In this case the second order diffraction will be
at 80o
at 64o
at 48o
there is no second order diffraction
D.
there is no second order diffraction
Angle of first-order diffraction (θ1) = 32o
We know that the angle of diffraction for the nth order ( θn ) is given by
d sin( θn ) = nλ
For first order diffraction we get
d sin32o = 1 × λ
λ = d sin 32o
Now for second order diffraction we get
d sin θ2 = 2 × λ
d sin θ2 = 2 × d sin32o
sin θ2 = 2 × sin 32o
= 2 × 0.529
sin θ2 = 1.06
Since the sine of any angle cannot be greater than 1. therefore there is no second order diffraction.
An object 5 cm tall is placed 1 m from a concave spherical mirror which has a radius of curvature of 20 cm. The size of the image is
0.11 cm
0.50 cm
0.55 cm
0.60 cm
The magnifying power of a compound microscope increase with
the focal length of objective lens is increased and that of eye lens is decreased
the focal length of eye lens is increased and that of objective lens is decreased
focal lengths of both objects and eye-piece are increased
focal lengths of both object and eye-piece
A thread is tied slightly loose to a wire frame as in figure and the frame is dropped into a soap solution and taken out. The frame is completely covered with the film. When the portion A is punctured with a pin, the thread
become concave towards A
become convex toward A
either (a) or (b) depending on the size of A with respect to B
remains in the initial position
Assertion: The colour of the green flower seen through red glass appears to be dark
Reason: Red glass transmits only red light.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion: It is essential that all the lines available in the emission spectrum will also be available in the absorption spectrum.
Reason: The spectrum of hydrogen atom is only absorption spectrum.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion: A double convex lens ( μ = 1.5 ) has focal length 10 cm. When the lens is immersed in water ( μ = 4/3 ) its focal length becomes 77 cm.
Reason:
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion: Diode lasers are used as optical sources in optical communication.
Reason: Diode lasers consume less energy.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion: Stopping potential depends upon the frequency of incident light but is independent of the intensity of the light.
Reason: The maximum kinetic energy of the photoelectrons is proportional to stopping potential.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
Assertion: 90Sr from the radioactive fall out from a nuclear bomb ends up in the bones of human beings through the milk consumed by them. It causes impairment of production of red blood cells.
Reason: The energies β-particles emitted in the decay of 90Sr damage the bone marrow.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false