Download App

Ray Optics and Optical Instruments — Physics STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 SciencePhysicsRay Optics and Optical Instruments1 Mark
MCQ

An object is placed at a distance u from a simple microscope of focal length f. The angular magnification obtained depends:

  • A
    On f but not on u.
  • B
    On u but not on f.
  • C
    On f as well as u.
  • D
    Neither on f nor on u.
✓

Answer

  1. On f as well as u.

Explanation:

​The angular magnification is the ratio of the angle subtended by the image to the angle subtended by the object on an unaided eye.

In a simple microscope,

$\text{m}=\frac{\frac{\text{h}}{\text{x}}}{\frac{\text{h}}{\text{D}}}$

Here,

u = Object distance from the lems 

D = Image distance form the lens

h = Height of the object

In normal adjustment, the object is placed at a distance equal to focal length (f) from the lens and then magnification is given by m

$=\frac{\text{D}}{\text{f}}$

for $\text{u}<\text{f},\text{ m}=\frac{\text{D}}{\text{f}}+1$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "M.C.Q [1M]" from Ray Optics and Optical Instruments→Ray Optics and Optical Instruments — all question types→Physics STD 12 Science question papers→Bihar Board STD 12 Science question papers→Bihar Board question paper generator→

Similar questions

The equivalent capacitance in the circuit between A and B will be

(a) 1 μF

(b) 2 μF

(c) 3 μF

(d)  
→
How will you relate velocity of cathode rays to c, if ‘c' denotes the velocity of light?
→

An achromatic combination of lenses produce:

→
In the arrangement shown in figure, the ends P and Q of an inextensible string move downwards with uniform speed u. Pulleys A and B are fixed. The mass M moves upwards with a speed:

  1. $2\text{u}\cos\theta$

  2. $\frac{\text{u}}{\cos\theta}$

  3. $\frac{\text{2u}}{\cos\theta}$

  4. $\text{u}\cos\theta$

→

The maximum illumination on a screen at a distance of 2 m from a lamp is 25 lux. The value of total luminous flux emitted by the lamp is

(a) 1256 lumen

(b) 1600 lumen

(c) 100 candela

(d) 400 lumen
→

Solid targets of different elements are bombarded by highly energetic electron beams. The frequency (f) of the characteristic X-rays emitted from different targets varies with atomic number Z as

(a) f ∝  

(b) f ∝  

(c) f ∝ Z  

(d) f ∝

→
Light travels in a ________ path:
→
For harder X-rays:
  1. The wavelength is higher.
  2. The intensity is higher.
  3. The frequency is higher.
  4. The photon energy is higher.
→

The following diagram indicates the energy levels of a certain atom when the system moves from 2E level to E, a photon of wavelength λ  is emitted. The wavelength of photon produced during its transition from   level to E is

 (a) λ/3

(b) 3 λ/4

(c) 4 λ/3  

(d) 3 λ
→
The work function of a metal is hv0. Light of frequency v falls on this metal. The photoelectric effect will take place only if:
→