CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon


Question

If the focal lengths of objective and eye-lens of a microscope are 1.2cm and 3cm respectively and the object is put 1.25cm away from the objective lens and the final image is formed at infinity, then magnifying power of the microscope is


A
150
loader
B
200
loader
C
250
loader
D
400
loader

Solution

The correct option is B 200
$$f_o = 1.2cm$$ 
$$u_e = f_e$$
$$f_e = 3cm$$ 
$$m_\infty = \dfrac {v_0}{u_0} \dfrac {D}{f_e}$$

$$u_0 = 1.25cm$$ $$L_\infty  = r_0 + f_0$$

$$\gamma_e = \infty $$

$$M = ? $$
$$\dfrac {1}{v_0} - \dfrac {1}{1.25} = \dfrac {-1}{1.2} \Rightarrow \dfrac {1}{v_0} = \dfrac {-1}{1.2} + \dfrac {1}{1.25} = \dfrac {-0.05}{1.2 \times 1.25} = \dfrac {-1}{30}$$

$$v_0 = 30\ cm$$

$$M_\infty = \dfrac {30}{1.25} \times \dfrac {2.5}{3} = 200$$

Physics
NCERT
Standard XII

Suggest Corrections
thumbs-up
 
0


similar_icon
Similar questions
View More


similar_icon
Same exercise questions
View More


similar_icon
People also searched for
View More



footer-image