At what angle must a light ray fall on the surface of an equilateral prism so that its angle of minimum deviation will be 20°?
OR
Calculate the time required by a ray of light to traverse a glass slab of thickness 2 mm. The refractive index of glass=1.5.
WBBSE
Class X
Physical Science
Light – Reflection and Refraction
02 Mark
2024
Angle of the prism = 60°
Angle of minimum deviation (δ) = 20°
We know,
Angle of minimum deviation (δ) = 2i – A
or, δ = 2i – A
or, 2i = δ + A = 20° + 60° = 80°
or, i = 40°
OR
Given
- Distance = 2 mm = 2 × 10⁻³ m
- Speed of light in vacuum (c) = 3 × 10⁸ m/s
- Refractive index of glass (μ) = 1.5
μ = \text{c}\over\text{v}
or, v = \text{c}\over\text{μ}
= \text{3 × 10⁸}\over\text{1.5}
= 2 × 10⁸ m/s
Related Questions
More WBBSE Moderate level questions
1/12
Q.
For which value of the angle of incidence in refraction of light is Snell’s law...
A.
Snell’s law is not applicable when the angle of incidence is 0°.
Q.
How can the given conversion be carried out?
A.
The given conversion of ethene (H₂C = CH₂) to ethane (H₃C –...
Q.
What type of lens is used as a magnifying glass?
A.
Convex lens Explanation: Convex lens forms virtual, erect, magnified image for objects...
Q.
Which type of mirror produces virtual, diminished and erect image?
A.
(c) Convex mirror Explanation: A convex mirror always forms an image which...
Q.
Which parameter remains unaltered during refraction of light?
A.
(c) Frequency Explanation: During refraction, a light ray bends because its speed...
Q.
Write the names of two bio-degradable polymers.
A.
Examples of biodegradable polymers : Polylactic acid (PLA) Polyhydroxybutyrate (PHB)
Q.
Explain the difference between minerals and ores.
A.
Minerals Ores Minerals are naturally occurring substances found in the Earth’s crust....
Q.
Name two copper containing alloys. State one use of each alloy.
A.
Two copper alloys: Copper Alloy Composition Uses Brass Copper (Cu): 60–80% Zinc...
Q.
State the resistance of 220 V – 100 W bulb
A.
Power (P) = Resistance (R) = = = = 484 Ω
Q.
Write whether the following statement is true or false: If coefficient of linear expansion of...
A.
True Explanation: Coefficient of cubical expansion γ = 3 × coefficient of...
Q.
What is the number of molecules present in 16 g of O₂ at S.T.P.?
A.
3.011 × 10²³ Explanation: Given mass = 16 g Molecular mass =...
Q.
Write whether the following statement is true or false: According to Charles’ law, at (–)...
A.
False Explanation: Charles' law states volume becomes zero at absolute zero (-273°C),...