Tuesday, 8 November 2016

9 physical optics MCQs

Chapter 9 physical optics is an important chapter of Physics of first year.Focal length,lens power,optical fibre,speed of light and other optical topics are of great importance.

Physical optics MCQs

1.            The speed of distant stars and galaxies can be calculated by the use of
(c) relativity                          (d) all of these

2.            Light reaches Earth from the Sun in about
(a)        15 ½ minutes                   (b) 10 minutes
(c) 8 ½ minutes                     (d) 6 ½ minutes
3.            The danger signals are red while the eye is most sensitive to yellow because
(a)        scattering of yellow colour is less than  that of red
(b)        red light is longer in wavelength than yellow light
(c)        scattering in red is less than in yellow
(d)       red colour is more intense than yellow

4.            The spreading of light after passing through a pinhole is called
(a)        dispersion                         (b) scattering
(c) diffraction                        (d) all of these

5.            The minimum distance between an object and its real image in a convex lens is
(a)        2 f                                     (b) 3 f
(c) 4 f                                    (d) 6 f

6.            When a convex lens of focal length f is immersed in a liquid of refractive index n less than that of the lens, then its focal length
(a)        decreases                         (b) increases
(c) remains the same             (d) becomes the same

7.            The ability of an instrument to reveal the minor details of an object is its
(a)        resolution                          (b) magnification
(c) resolving power                (d) none of these

8.            The resolving power of an astronomical telescope depends upon
(a)        the focal length of the objective           (b) the focal length of eyepiece
(c)  the diameter of the objective lens.
(d)  the diameter of the eyepiece lens

9.            Multimode step index fibre is useful for
(a)        long distance
(b)        short distance
(c)        neither long nor short distance
(d)       neither of these

10.         The disadvantages of a step index fibre can be overcome by using
(a)        impurities in the fibre       (b) graded index fibre

(c) a highly pure glass           (d) none of these

Optical instruments MCQs

1.            The unit of magnifying power is
(a)        jolue                                  (b) watt
(c) diopter                             (d) no unit

2.            The focal length and radius of curvature of a lens are related by
(a)        f = 2R                               (b) R = 2f
(c) R = f                                (d) none of these