Download App

9. Ray optics abd optical instruments — Physics STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 SciencePhysics9. Ray optics abd optical instruments1 Mark
MCQ
A biconvex lens forms a real image of an object placed perpendicular to its principal axis. Suppose the radii of curvature of the lens tend to infinity. Then the image would
  • A
    Disappear
  • B
    Remain as real image still
  • ✓
    Be virtual and of the same size as the object
  • D
    Suffer from aberrations
✓

Answer

Correct option: C.
Be virtual and of the same size as the object
c
(c) $\frac{1}{f} = (\mu - 1)\left( {\frac{1}{{{R_1}}} - \frac{1}{{{R_2}}}} \right)$
For biconvex lens ${R_2} = - {R_1}$

$\therefore $ $\frac{1}{f} = (\mu - 1)\left( {\frac{2}{R}} \right)$
Given $R = \infty $ $\therefore $ $f = \infty $, so no focus at real distance.

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 (1 Marks)" from 9. Ray optics abd optical instruments→9. Ray optics abd optical instruments — all question types→Physics STD 12 Science question papers→CBSE Board STD 12 Science question papers→CBSE Board question paper generator→

Similar questions

A zinc ball of radius $1 \,cm$ charged to a potential $-0.5 \,V$. The ball is illuminated by a monochromatic ultraviolet light with a wavelength $290 \,nm$. The photoelectric threshold for zinc is $332 \,nm$. The potential of ball after a prolonged exposure to the ultraviolet is ............. $V$
→
In Boolean algebra $A.B=Y$ implies the :
→
An electron is allowed to move with constant velocity along the axis of current carrying straight solenoid.

$A.$ The electron will experience magnetic force along the axis of the solenoid.

$B.$ The electron will not experience magnetic force.

$C.$ The electron will continue to move along the axis of the solenoid.

$D.$ The electron will be accelerated along the axis of the solenoid.

$E.$ The electron will follow parabolic path-inside the solenoid.

Choose the correct answer from the options given below:

→
$\frac{{2.5}}{\pi }\mu F$ capacitor and $3000-ohm$ resistance are joined in series to an $ac$ source of $200\, volt$ and $50se{c^{ - 1}}$ frequency. The power factor of the circuit and the power dissipated in it will respectively
→
The reciprocal of resistance is
→
If maximum velocity with which an electron can be emitted from a photo cell is $4 \times {10^8}\,cm/\sec $, the stopping potential is ................ $volt$ (mass of electron $= 9 \times 10^{-31} \,kg$)
→
Which of the following plots may represent the thermal energy produced in a resistor in a given time as a function of the electric current
→
A coil of self inductance $10\,mH$ and resistance $0.1\,\Omega $ is connected through a switch to a battery of internal resistance $0.9\,\Omega $. After the switch is closed the time taken for the current to attain $80\%$ of the saturation values is: [take $ln\,5 = 1.6$ ]
→
Each of two large conducting parallel plates has one sided surface area $A$. If one of the plates is given a charge $Q$ whereas the other is neutral, then the electric field at a point in between the plates is given by
→
In Young's double slit experiment, if L is the distance between the slits and the screen upon which interference pattern is observed, x is the average distance between the adjacent fringes and d being the slit separation. The wavelength of light is given by
→