Download App

Dispersion and Spectra — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsDispersion and Spectra1 Mark
Question
Which of the following quantities increase when wavelength is increased? Consider only the magnitudes.
  1. The power of a converging lens.
  2. The focal length of a converging lens.
  3. The power of a diverging lens.
  4. The focal length of a diverging lens.
✓

Answer

  1. The focal length of a converging lens.
  1. The focal length of a diverging lens.

Explanation:

The focal length of a lens is inversely proportional to the refractive index of the lens and the refractive index of the lens is inversely proportional to the square of wavelength. Therefore, the focal length is directly dependent on wavelength; it increases when the wavelength is increased.

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 Dispersion and Spectra→Dispersion and Spectra — all question types→Physics STD 12 Science question papers→Gujarat Board STD 12 Science question papers→Gujarat Board question paper generator→

Similar questions

The materials having high resistance to the passage of electricity are called as:
→

The capacitance of an air filled parallel plate capacitor is 10μμF . The separation between the plates is doubled and the space between the plates is then filled with wax giving the capacitance a new value of 40. The dielectric constant of wax is

(a) 12.0   

(b) 10.0

(c) 8.0

(d) 4.2
→
Permanent magnets should have:
→

The capacitance between the points A and B in the given circuit will be

(a) 1 μF

(b) 2 μF

(c) 3 μF   

(d) 4 μF
→
Which of the following about potential at a point due to a given point charge is true?
The potential at a point P due to a given point charge.
→
In an LED device, the intensity of emitted light:
→
The frequency of electromagnetic wave in free space is 2 MHz. When it passes through a region of relative permittivity $\in_\text{r}=4.0,$ then its wave length __________ & frequency ______________
→
If we double the radius of a coil keeping the current through it unchanged, then the magnetic field at any point at a large distance from the centre becomes approximately:
→
An electromagnetic field exists only when there is.
→
A very long bar magnet is placed with its north pole coinciding with the centre of a circular loop carrying as electric current i. The magnetic field due to the magnet at a point on the periphery of the wire is B. The radius of the loop is a. The force on the wire is:
→