+91-8076753736 support@wiredfaculty.com
Wired Faculty Logo
Wired Faculty Logo Wired Faculty

Sponsor Area

Acids, Bases And Salts

Question
CBSEENSC10014622
Wired Faculty App

The image of a candle flame placed at a distance 30 cm from a spherical lens is formed on a screen placed at a distance of 60 cm from the lens. Identify the type of lens and calculate its focal length. If the height of the flame is 2.4 cm, find the height of its image.

Solution

Given,

Object distance, u = − 30 cm

Image distance, v = 60 cm

Height of the object, h = 2.4 cm

Using lens formula,

 
1 over straight f space equals 1 over straight v minus 1 over straight u 1 over straight f space equals 1 over 60 minus fraction numerator 1 over denominator negative 30 end fraction equals 1 over 60 plus 1 over 30 equals fraction numerator 1 plus 2 over denominator 60 end fraction equals 3 over 60 equals 1 over 20 straight f equals plus 20 space cm Since comma space the space focal space length space is space positive comma space the space lens space is space convex space lens. Now comma Magnification comma space straight m equals space straight v over straight u equals straight h to the power of apostrophe over straight h equals space fraction numerator 60 over denominator negative 30 end fraction equals fraction numerator straight h apostrophe over denominator 4 end fraction straight h apostrophe space equals negative 4.8 space cm space is space the space required space height space of space the space image

 

    

    

 

Some More Questions From Acids, Bases and Salts Chapter

What is the wavelength range of visible light? What is the importance of this wavelength range?

Define a ray of light and a beam light. What are the different types of beams of light?

What is an optical medium? How can we classify different media on the basis of their behaviour towards light?

What do you mean by reflection, refraction and absorption of light?

Which type of phenomenon (reflection or refraction) occurs when light falls on (i) a highly polished surface like a mirror and (ii) a transparent medium like glass or water?

What is meant by the optical image of an object?

What are real and virtual images? Can these images be obtained on a screen? Give reasons in support of your answer.

Give three points of differences between real and virtual images.

What is a mirror? Mention the different types of mirrors commonly used.

Define the following terms in connection with reflection of light:
Incident ray, reflected ray, point of incidence, normal, angle of incidence and angle of reflection.

Sponsor Area

Mock Test Series

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation