Department of Pre-University Education, KarnatakaPUC Karnataka Science Class 12

Three Light Sources A, B and C Emit Equal Amount of Radiant Energy per Unit Time. the Wavelengths Emitted by the Three Source Are 450 Nm, 555 Nm and 700 Nm Respectively. - Physics

Advertisement Remove all ads
Advertisement Remove all ads
Advertisement Remove all ads
Fill in the Blanks

Three light sources A, B and C emit equal amount of radiant energy per unit time. The wavelengths emitted by the three source are 450 nm, 555 nm and 700 nm respectively. The brightness sensed by an eye for the sources are XA, XB and XC respectively. Then, ________ .


  • XA > XB, XC > XB

  • XA > XB, XB > XC

  • XB > XA, XB > XC

  • XB > XA, XC > XB

Advertisement Remove all ads


XB > XA, XB > XC


Wavelength of light B is 555 nm. It has the highest luminosity; hence, XB will be highest.

Again, 450 nm is nearer to 555 nm than 700 nm.

∴ 555 - 450 = 105

But 700 - 555 = 145

So, XA's brightness will be greater than that of XC.

Concept: Light Process and Photometry
  Is there an error in this question or solution?


HC Verma Class 11, Class 12 Concepts of Physics Vol. 1
Chapter 22 Photometry
MCQ | Q 2 | Page 454

View all notifications

      Forgot password?
View in app×