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# Light - Reflection and Refraction

10th Class - CBSE - Physics - 2829 Questions - 0 Concepts

#### Important Questions

Q1 Single Correct Hard
The magnifications produced by a convex lens for two different positions of an object are ${ m }_{ 1 }$ and ${ m }_{ 2 }$ respectively $\left( { m }_{ 1 }\ >\ { m }_{ 2 } \right)$. If d is the distance of separation between the two positions of the object then the focal length of the lens is
• A. $\sqrt { { m }_{ 1 }{ m }_{ 2 } }$
• B. $\dfrac { d }{ \sqrt { { m }_{ 1 }-{ m }_{ 2 } } }$
• C. $\dfrac { d{ m }_{ 1 }{ m }_{ 2 } }{ { m }_{ 1 }-{ m }_{ 2 } }$
• D. $\dfrac { d }{ { m }_{ 1 }-{ m }_{ 2 } }$

Asked in: Physics - Light - Reflection and Refraction

1 Verified Answer | Published on 07th 09, 2020

Q2 Single Correct Hard
A concave shaving mirror has a radius of curvature of 35.0 cm. It is positioned so that the (upright) image of a mans face is 2.50 times the size of the face. How far is the mirror from the face?
• A. 5.25 cm
• B. 21.0 cm
• C. 10.5 cm
• D. 42 cm

Asked in: Physics - Light - Reflection and Refraction

1 Verified Answer | Published on 07th 09, 2020

Q3 Multiple Correct Hard
A student performed the experiment of determination of focal length of a concave mirror by u v method using an optical bench of length 1.5 meter. The focal length of the mirror used is 24 cm. The maximum error in the location of the image can be 0.2 cm. The 4 sets of (u, v) values recorded by the student(in cm) are: (42, 56), (48, 48), (66, 33), (78, 39). The data set(s) that cannot come from experiment and is (are) incorrectly recorded, is (are):
• A. (42, 56)
• B. (48, 48)
• C. (66, 33)
• D. (78, 39)

Asked in: Physics - Light - Reflection and Refraction

1 Verified Answer | Published on 07th 09, 2020

Q4 Subjective Hard
A small linear object of length $b$ is placed at a distance $u$ from the pole of the concave mirror along the axis the focal length of mirror is $f$. The length of image will be

Asked in: Physics - Light - Reflection and Refraction

1 Verified Answer | Published on 07th 09, 2020

Q5 Single Correct Hard
Refraction of the light from the air to glass and from air to water are shown in the figure (i) and figure (ii) below. The value of an angle $\theta$ in the case of refraction as shown in the figure (iii) will be
• A. 30
• B. 60
• C. 41
• D. 35

Asked in: Physics - Light - Reflection and Refraction

1 Verified Answer | Published on 07th 09, 2020

Q6 Single Correct Hard
A convex lens of radii of curvature 20 cm and 30 cm respectively. It is silvered at the surface which has smaller radius of curvature. Then it will behave as $(\mu_g \, = \, 1.5)$
• A. concave mirror with equivalent focal length $\frac{30}{11} cm$
• B. convex mirror with equivalent focal length $\frac{30}{11} cm$
• C. convex mirror with equivalent focal length $\frac{60}{11} cm$
• D. concave mirror with equivalent focal length $\frac{60}{11} cm$

Asked in: Physics - Light - Reflection and Refraction

1 Verified Answer | Published on 07th 09, 2020

Q7 One Word Hard
Sunlight of intensity $1.3 kW m^{-2}$ is incident normally on a thin convex lens of focal length $20 cm$. Ignore the energy loss of light due to the lens and assume that the lens aperture size is much smaller than its focal length. The average intensity of light, in $kW m^{-2}$, at a distance $22 cm$ from the lens on the other side is _____.

Asked in: Physics - Light - Reflection and Refraction

1 Verified Answer | Published on 07th 09, 2020

Q8 Single Correct Hard
A bi-convex lens is formed with two plano-convex lenses as shown in the figure. Refractive index n of the first lens is 1.5 and that of the second lens is 1.2. Both curved surfaces are of the same radius of curvature R = 14 cm. For this bi-convex lens, for an object distance of 40 cm, the image distance will be
• A. $-280.0 cm$
• B. $21.5 cm$
• C. $13.3 cm$
• D. $440.0 cm$

Asked in: Physics - Light - Reflection and Refraction

1 Verified Answer | Published on 07th 09, 2020

Q9 Single Correct Hard
A rod $1.5 m$ longis placed along the principal axis of a convex mirror of focal length $60 cm$. The near and of the rod is $1 m$ from the pole of the convex mirror. The length of the image of the rod is
• A. $15 cm$
• B. $14.44 cm$
• C. $6.62 cm$
• D. $10.88 cm$

Asked in: Physics - Light - Reflection and Refraction

1 Verified Answer | Published on 07th 09, 2020

Q10 Single Correct Hard
A ray of light on a concave mirror of radius of curvature '$R$' at a height $\cfrac { \sqrt { 3 } }{ 2 } R$ from the principal axis as shown. The net deviation in ray caused by the mirror is:
• A. $\pi$
• B. $\cfrac { \pi }{ 2 }$
• C. $\cfrac { \pi }{ 6 }$
• D. $\cfrac { 2\pi }{ 3 }$

Asked in: Physics - Light - Reflection and Refraction

1 Verified Answer | Published on 07th 09, 2020

Questions 122475
Subjects 10
Chapters 93
Enrolled Students 65