Reflection of Light Exe-7C Numericals Concise Physics ICSE Class-9 Selina Publishers. There is the solutions of **Numerical** type Questions of your latest textbook which is applicable in 2024-25 academic session**. **Visit official Website CISCE for detail information about ICSE Board Class-9

## Reflection of Light Exe-7C Numericals

Concise Physics ICSE Class-9 Selina Publishers solutions

Board | ICSE |

Class | 9 |

Subject | Physics |

Writer / Publication | Concise Selina Publishers |

Chapter-7 | Reflection of Light |

Exe-7C | Sphericals Mirrors Image Formation |

Topics | Solution of Exe-7(C) Numericals |

Academic Session | 2024-2025 |

Spherical Mirrors Numerical Problems

Spherical Mirrors Numerical Problems

Reflection of Light Exe-7C Numericals Concise Physics ICSE Class-9 Selina Publishers

**page -189**

**Que -1: The radius of curvature of a convex mirror is 40 cm. Find its focal length.**

Solution- Focal length = ½ (Radius of curvature)

Or, f = 402 = 20 cm.

**Que-2: The focal length of a concave mirror is 10 cm. Find its radius of curvature.**

Solution- Radius of curvature = 2 × focal length

Or, R = 2f = 2 × 10 = 20 cm.

**Que-3: An object of height 2 cm is placed at a distance of 20 cm in front of a concave mirror of a focal length of 12 cm. Find the position, size, and nature of the image.**

Solution-

The image is 30 cm in front of the mirror, 3 cm high, real, inverted and magnified.

**Que-4: An object is placed at 4 cm distance in front of a concave mirror of radius of curvature 24 cm. Find the position of image. Is the image magnified?**

Solution-

The image is 6 cm behind the mirror.

Yes the image is magnified.

**Que-5: At what distance from a concave mirror of focal length 25 cm should an object be placed so that the size of image is equal to the size of the object.**

Solution- The size of the image is equal to the size of the object if the object is placed at the centre of curvature of a concave mirror.

Hence, the object should be placed at 50 cm.

**Que-6: An object 5 cm high is placed at a distance 60 cm in front of a concave mirror of focal length 10 cm. Find the position and size of the image.**

Solution-

The position of the object is 12 cm in front of the mirror.

Its size is 1 cm.

**Que-7: A point light source is kept in front of a convex mirror at a distance of 40 cm. The focal length of the mirror is 40 cm. Find the position of image.**

Solution-

The image is behind the mirror at a distance 20 cm.

**Que-8: When an object of height 1 cm is kept at a distance 4 cm from a concave mirror, its erect image of height 1.5 cm is formed at a distance 6 cm behind the mirror. Find the focal length of mirror**

Solution-

A ray passing parallel to the principal axis passes through the focal point after reflection. Hence, the focal length is 12 cm.

**Que-9: An object of length 4 cm is placed in front of a concave mirror at distance 30 cm. The focal length of mirror is 15 cm.**

- Where will the image form?
- What will be the length of image.

Solution-

**Que-10: A concave mirror forms a real image of an object placed in front of it at a distance 30 cm, of size three times the size of object. Find (a) the focal length of mirror (b) position of image.**

Solution-

**Que-11: A concave mirror forms a virtual image of size twice that of the object placed at a distance 5 cm from it.**

Find : (a) the focal length of the mirror (b) position of image

Solution-

–

**Que-12: The image formed by a convex mirror is of size one third the size of object. How are u and v image?**

Solution-

**Que-13: The erect image formed by a concave mirror is of size double the size of object. How are u and v image?**

Solution- Magnification is

**Que-14: The magnification for a mirror is -3. How are u and v related?**

Solution- Magnification of a mirror is

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