UKPSC Lab Assistant Higher Education (Group-C) Exam 2024 Physics Question Paper PDF

1. What is the focal length of combination of a convex lens of focal length 30 cm in contact with a concave lens of focal length 20 cm ? (Ignore thickness of the lenses).

(a) 50 cm

(b) 60 cm

(c) 10 cm

(d) 25 cm

2. A giant refracting telescope at an observatory has an objective lens of focal length 15 m. If an eyepiece of focal length 1.0 cm is used, what is the angular magnification of the telescope?

(a) 1600

(b) 16

(c) 15

(d) 1500

3. When white light passes through the prism, which colour light deviates more?

(a) Red

(b) Orange

(c) Violet

(d) Yellow

4. What is the equivalent focal length of two thin convex lenses separated by a distance d?

(a) $\frac{1}{f} = \frac{1}{f_1} + \frac{1}{f_2} + \frac{d}{f_1 f_2}$

(b) $\frac{1}{f} = \frac{1}{f_1} - \frac{1}{f_2} + \frac{d}{f_1 f_2}$

(c) $f=f_1+f_2+\frac{f_1f_2}{d}$

(d) $\frac{1}{f} = \frac{1}{f_1} + \frac{1}{f_2} - \frac{d}{f_1 f_2}$

5. In Young's double slit experiment, when the distance between the slits is halved and distance between slits and screen is doubled. The fringe width will be:

(a) unchanged

(b) halved

(c) doubled

(d) quadrupled

6. In a Young's double slit experiment, the distance between slits is 0.5 cm and the distance of screen from slits is 1 m. If the wavelength of light used is 5000 Å, then fringe width is :

(a) 0.1 cm

(b) 0.01 cm

(c) 10 cm

(d) 1 cm

7. In Young's double slit experiment, the distance between the slits is gradually increased. The width of fringes in fringe system

(a) increases

(b) remains same

(c) decreases

(d) first increases and then decreases

8. On reflection from denser to a rarer medium, the path difference introduced is :

(a) Zero

(b) $\lambda/2$

(c) $\lambda$

(d) $2\lambda$

9. $\mu = \tan i_p$ is known as :

(a) Ohm's law

(b) Newton's law

(c) Brewster's law

(d) Faraday's law

10. If $\theta$ is polarising angle, the refractive index $\mu$ of material is given by :

(a) $\sin \theta$

(b) $\cos \theta$

(c) $\tan \theta$

(d) $\cos^{-1} \theta$

11. The phenomenon of diffraction indicates :

(a) Wave nature

(b) Particle nature

(c) Both (a) and (b)

(d) None of these

12. In a diffraction experiment with light waves, the size of obstacle in path should be of the order of :

(a) 1 mm

(b) 0.1 mm

(c) $10^{-4}$ mm

(d) 1 cm

13. The diffraction phenomenon happens

(a) only for mechanical waves

(b) only for electromagnetic waves

(c) only for visible light waves

(d) for both mechanical and electromagnetic waves

14. In a double-slit experiment, the angular width of a fringe is found to be 0.2° on a screen placed 1 m away. The wavelength of light used is 600 nm. What will be the angular width of the fringe if the entire experimental apparatus is immersed in water ? (Refractive index of water = 4/3).

(a) 0.33°

(b) 0.11°

(c) 0.15°

(d) 0.05°