CBSE
Multiple Choice QuestionsTwo polaroids are crossed. If now one of them is rotated through 30° and unpolarized light of intensity IO is incident on the first polaroid, then the intensity of transmitted light will be
Io/4
3Io/4
3Io/8
Io/8
Assertion: A beam of charged particles is employed in the treatment of cancer.
Reason: Charged particles on passing through a material medium lose their energy by causing ionization of the atoms along their path.
if both assertion and reason are true and the reason is the correct explanation of the assertion
if both assertion and reason are true and the reason is not the correct explanation of the assertion
if assertion is true but reason is false
if both assertion and reason are false statements
Two coherent monochromatic light beams of amplitude 3 and 5 units are superposed. The maximum and minimum possible intensities in the resulting beams are in the ratio
4 : 2
16 : 1
8 : 2
4 : 2
A double slit experiment is performed with light of wavelength 500 nm. A thin film of thickness 2 μm and refractive index 1.5 is introduced in the path of the upper beam. The location of central maximum will
remain unshifted
shift downward by nearly two fringes
shift upward by nearly two fringes
shift downward by 10 fringes
Assertion: The stars twinkle while the planets do not.
Reason: The stars are much bigger in size than the planets.
if both assertion and reason are true and the reason is the correct explanation of the assertion
if both assertion and reason are true and the reason is not the correct explanation of the assertion
if assertion is true but reason is false
if both assertion and reason are false statements
Assertion: Skiers uses air glasses.
Reason: Light reflected by snow is partially polarised.
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 assertion is false but reason is true.
Assertion: When tiny circular obstacle is placed in the path of light from some distance, a bright spot is seen at the centre of the shadow of the obstacle.
Reason: Destructive interference occurs at the centre of the shadow.
If both the assertion and reason are true and reason is a correct explanation of the assertion.
If both assertion and reason are true but assertion is not a correct explanation of the assertion.
If the assertion is true but the reason is false
If both assertion and reason are false.
The distance between two coherent sources is 1 mm. The screen is placed at a distance of 1 m from the sources. If the distance of the third bright fringe is 1.2 mm from the central fringe, the wavelength of light used is
4000 Å
5000 Å
6000 Å
7200 Å
Assertion: S.I. units are logical and coherent.
Reason: S.l. system of units is a rationalised system.
If both the assertion and reason are true and reason is a correct explanation of the assertion.
If both assertion and reason are true but assertion is not a correct explanation of the assertion.
If the assertion is true but the reason is false.
If both assertion and reason are false.
Assertion: Coloured spectrum is seen when we look through a muslin cloth.
Reason: It is due to the diffraction of white light on passing through fine slits
If both the assertion and reason are true and reason is a correct explanation of the assertion
If both assertion and reason are true but assertion is not a correct explanation of the assertion.
If the assertion is true but the reason is false.
If both assertion and reason are false.
