Home
Class 12
PHYSICS
A : The direction of a light is always ...

A : The direction of a light is always perpendicular to wavefront
R : A ray of light is a line perpendicular to a wavefront in the direction of propagation.

A

Both A and R are true and R is the correct explanation of A

B

Both A and R are true and R is not the correct explanation of A

C

A is true and R is false

D

Both A and R are false

Text Solution

AI Generated Solution

The correct Answer is:
To analyze the statements given in the question, we need to evaluate each statement individually and determine their validity. ### Step 1: Understanding the First Statement (A) The first statement is: "The direction of a light is always perpendicular to wavefront." - **Explanation**: A wavefront is defined as the locus of points that are in the same phase of a wave. For light waves, the direction of propagation of the wave is perpendicular to the wavefront. This means that if we consider a wavefront as a flat surface, the light rays (which represent the direction of light) will always make a right angle with this surface. - **Conclusion**: The statement A is **True**. ### Step 2: Understanding the Second Statement (R) The second statement is: "A ray of light is a line perpendicular to a wavefront in the direction of propagation." - **Explanation**: A ray of light is indeed represented as a straight line that indicates the path along which light energy travels. By definition, this ray is perpendicular to the wavefront, which means that it points in the direction of the wave's propagation. - **Conclusion**: The statement R is also **True**. ### Step 3: Evaluating the Relationship between A and R Now that we have established that both statements A and R are true, we need to determine if R is a correct explanation of A. - **Analysis**: Since R accurately describes the relationship between the direction of light and the wavefront, we can conclude that R is indeed a correct explanation for A. ### Final Conclusion Both statements A and R are true, and R is a correct explanation of A. ### Summary - Statement A: True - Statement R: True - R is a correct explanation of A.
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • WAVES OPTICS

    AAKASH SERIES|Exercise EXERCISE -II (INTERFERENCE)|26 Videos

  • WAVES OPTICS

    AAKASH SERIES|Exercise EXERCISE -II (DIFFRACTION)|17 Videos

  • WAVES OPTICS

    AAKASH SERIES|Exercise EXERCISE -IA (ASCENDING AND DSCENDING ORDER TYPE QUESTIONS)|6 Videos

  • WAVES

    AAKASH SERIES|Exercise EXERCISE-III (Doppler effect :)|15 Videos

Similar Questions

Explore conceptually related problems

Direction of light is detected by

Assertion In electromagnetic wave, if direction of veriations of electric and magnetic field are perpendicular to each other and also perpendicular to the direction of wave propagation. Reason Electronegative waves are transverse in nature.

Knowledge Check

  • Assertion : Electromagnetic waves are transverse in nature Reason : The electric and magnetic fields in electromagnetic waves are perpendicular to each other and to the direction of propagation.

    A
    If both assertion and reason are true and reason is the correct explanation of assertion
    B
    If both assertion and reason are true but reason is not the correct explanation of assertion
    C
    If assertion is true but reason is false
    D
    If both assertion and reason are false

    • Similar Questions

    Explore conceptually related problems

    Wavefront of a wave has direction with wave motion

    The direction ratios of the perpendicular from the origin to a plane are 12,-3,4 and the length of the perpendicular is 5. Find the equation of the plane.

    The ray of light after striking the mirror moves in same direction.

    How is a wavefront related to the direction of corresponding rays ?

    Huygen was the first scientist who proposed the idea of wave theory of light. He said that the light propagates in form of wavefronts. A wavefront is an imaginary surface at every point of which waves are in the same phase. For example the wavefronts for a point source of light is collectionof concentric spheres which have centre at the origin. w_(1) is a wavefront. w_(2) is another wavefront. The redius of the wavefront at time 't' is 'ct' in this case where 'c' is the speed of light. The direction of propagation of light is perpendicular to the surface of the wavefront. The wavefronts are plane wavefronts in case of a parallel beam of light. Huygen also said that every point of the wavefront acts as the source of secondary wavelets. The tangent drawn to all secondary wavelets at a time is the new wavefront at that time. The wavelets are to be consid-ered only in the forward direction ( i.e. the direction of propagation of light) and not in the reverse direction. If a wavefront w_(1) at time t is given, then to draw the wavefront at time t+Deltat0 take some points on the wavefront w_(1) and draw spheres of radius 'cDeltat'. They are called secondary wavelets Draw a surface w_(2) which is tangential to all these secondary wavelets. w_(2) is the wavefront at time 't+Deltat'. Huygen proved the laws of reflection and laws of refraction using concept of wavefronts. A point source of light is placed at origin, in air. The equation of wave front of the wave at time t, emitted by source at t=0, is (take refractive index of air as 1 )

    Will a vertical line and a horizontal line always be perpendicular to each other?

    A plane electromagnetic wave-varies sinusoidally at 900 MHz as it travels along the positive X Direction. The peak value of the electric field is 2mv//m and is directed pm direction. The average power per unit area perpendicular to the direction of propagation is

    Home
    Profile