Table of Contents
- 1 What is the reason for the change in the diameter of the rings on changing the refractive index of the medium between the glass plate and plano convex lens?
- 2 What is the diameter of Newton ring?
- 3 Why do Newton rings get closer as their order increases?
- 4 How are Newtons rings formed?
- 5 What are the factors which govern the radius of a ring?
- 6 How are Newton’s rings formed?
- 7 What is the principle of Newton’s rings formation?
- 8 How does the radius of a dark ring depend on curvature?
What is the reason for the change in the diameter of the rings on changing the refractive index of the medium between the glass plate and plano convex lens?
Because of the 180∘ phase reversal due to reflection of the bottom ray, the center where the two pieces touch is dark. Since the gap between the glasses increases radially from the center, the interference fringes form concentric rings. The thickness of the rings decreases as their diameter decreases.
What is the diameter of Newton ring?
In Newton’s ring experiment the diameter of n th and (n+8) bright rings are 4.2mm and 7mm respectively. Radius of curvature of lower surface of lens is 2m.
Why do Newton rings get closer as their order increases?
Rings get closer as the order increases (m increases) since the diameter does not increase in the same proportion. In transmitted light the ring system is exactly complementary to the reflected ring system so that the centre spot is bright.
Why is the radius of curvature of the lens kept large in Newton Ring experiment?
At the point of contact of lens and the plate thickness is zero, so optical path difference becomes only λ/2 which is condition for destructive interference. iv)When a planoconvex lens of large radius of curvature is placed on a flat glass plate, a thin film of air is trapped between lens and plate.
Why are Newtons rings circular?
The path difference between the reflected ray and incident ray depends upon the thickness of the air gap between lens and the base. As the lens is symmetric along its axis, the thickness is constant along the circumference of a ring of a given radius. Hence, Newton’s rings are circular.
How are Newtons rings formed?
The rings of Newton’s are formed as a result of interference which is between the light waves that are reflected from the top and bottom surfaces of the air film formed between the lens and glass sheet. When a ray is incident on the lens surface then it is reflected as well as refracted.
What are the factors which govern the radius of a ring?
Ans. The radius depends upon (i) wavelength of light used. (ii) refractive index ‘μ’ of enclosed film. (iii) radius of curvature R of convex lens.
How are Newton’s rings formed?
Formation of Newton’s Ring The rings of Newton’s are formed as a result of interference which is between the light waves that are reflected from the top and bottom surfaces of the air film formed between the lens and glass sheet. When a ray is incident on the lens surface then it is reflected as well as refracted.
What factors does the diameter of a ring depend on?
newton’s rings – q15 15) On which factors does the diameter of a ring depend? Ans: Diameter of a ring depends on the wavelength of light used, refractive index of the medium between lens and glass plate, order of the ring and radius of curvature of Planocovex lens.
How do you calculate R2 in newtons rings?
Newtons Rings Equation If R is the radius of curvature of the lens and r is the distance of the point under consideration to the point of contact of the lens and glass plate, then R 2 = (R-t) 2 + r 2 or, R 2 = R 2 – 2Rt + t 2 + r 2
What is the principle of Newton’s rings formation?
Principle of Newton’s Rings Formation 1 An air film of varying thickness is formed between lens and the glass sheet. 2 When a ray is incident on the surface of the lens, it is reflected as well as refracted. 3 When the refracted ray strikes the glass sheet, it undergoes a phase change of 180° on reflection.
How does the radius of a dark ring depend on curvature?
The radius of a dark ring is proportional to the radius of curvature of the lens by the relation, . Rings get closer as the order increases (m increases) since the diameter does not increase in the same proportion. In transmitted light the ring system is exactly complementary to the reflected ring system so that the centre spot is bright.