Physics Topic Thermodynamics and Optical Instrument:

Physics Topic  Thermodynamics and Optical Instrument:

1. Which of the following is incorrect regarding the first law of thermodynamics?
a. It is the restatement of the principle of conservation of energy
b. It is not applicable to any cyclic process
c. It introduces the concept of entropy
d. It introduces the concept of the internal energy

2. Which of the following statements is correct for any thermodynamics system?
a. The internal energy changes in all processes
b. Internal energy and entropy  are state functions

c. The change in entropy can never be zero
d. The work done in an adiabatic process is always zero

3. "Heat cannot by itself flow from a body at lower temperature to a body at higher temperature" is a statement as a consequence of
a. Conservation of mass
b. Conservation of momentum

c. First law of thermodynamics
d. Second law of thermodynamics

4. Which of the following parameters does not characterize the thermodynamic state of matter?
a. Work
b. Volume
c. Pressure
d. Temperature

5. The translational kinetic energy of gas molecules at temperature T gas is
a. ( 3 / 2 ) kT
b. ( 9 / 2 ) kT
c. ( 1 / 3 ) kT
d. ( 5 / 2 ) kT

6. The temperature of an ideal gas is increased from 120 K to 480 K. If at 120 K the root mean square velocity of the gas molecules is V then at 480 K it becomes
a. 4 V
b. 2 V
c. V / 2
d. V / 4

7. The temperature at which the root mean square velocity of hydrogen gas molecules is twice that at 10o C
a. 20o C
b. 40o C
c. 819o C
d. 859o C

8. Which of the following quantity is path independent?

a. Internal energy
b. Work done
c. amount of heat
d. Molar heat capacity of gases

9. The thermodynamics says the maximum work by a system occurs
a. During a spontaneous process at constant pressure
b. At constant temperature
c. A constant volume
d. Along a reversible path

10. Entropy is a measure of for an isolated system
a. Increase in orderliness
b. Gain of high level energy
c. Increase in potential energy
d. Increase in randomness

11. Which of the following is reversible process listed below are used to form Carnot Cycle?
a. Isometric , isobaric
b. Isometric , adiabatic
c. Isobaric , adiabatic
d. Isothermal , adiabatic

12. A door of refrigerator in a kitchen is open consider the kitchen as an insulated closed system the internal energy of the kitchen will
a. Rise
b. Fall
c. Remain same
d. Information is not sufficient

13. Telescopes are placed in space to view distant galaxies primarily
a. To get closer to the observed object
b. To avoid the absorption of the light or other radiations in the atmosphere of earth
c. to avoid having to steer the telescope against the earth's motion
d. To avoid the light pollution from the earth's populated areas

14. What is the most important fnction of telescope?
a. Magnification
b. Resolution
c. Light collection
d. None of above

15. The most serious disadvantage of refracting telescope is
a. Their extreme expense
b. Their awkward size
c. The inconvenient location of the focused image
d. Distortion of the image due to sagging and bending

16. Which of the following features determines the resolving power of telescope?
a. The diameter of the objective
b. The focal length of the objective
c. The focal length of eyepiece
d. Two of the above

17. Large telescopes are reflecting rather than refracting because
a. The light gathering power of mirrors is greater than that of lenses
b. Lenses more accurately bend light rays to the focus
c. Mirror are easier to support than lenses
d. No choice

18. Which of the following powers of a telescope does not depend directly on the diameter of the objective lens or mirrors?
a. Magnifying power
b. Light gathering power
c. Resolving power
d. None of the above

19. The image formed by an objective of a compound microscope is
a. Real and enlarged
b. Virtual and enlarged
c. Real and diminished
d. Virtual and diminished

20. A person having the nearest distance of distinct vision of 32 cm uses a reading lens of 8 cm focal length.The magnification of his reading lens is
a. 5
b. 4
c. 3
d. 2

21. Consider telecommunication through optical fibers. which of the folloeing statement is not true?
a. Optical fibers can  be of graded refractive index
b. Optical fibers have extremely low transmission loss
c. Optical fibers are subject to electromagnetic interference from outside
d. Optical fibers may have homogeneous core with a suitable cladding

22. A ray of light is incident at the glass water interference at an angle i. If it emerges finally parallel to the surface of water then rhe value of microg would be
a. ( 4 / 3 ) sin I
b. 1 / sin i
c. 4 / 3
d. 1

23. Spherical aberration in a thin lens can be reduced by
a. Using a monochromatic light
b. Using a doublet combination
c. Using a circular annular ask over the lens
d. Increasing the size of lens
24. A convex lens of focal length  40 cm is in contact  with a concave lens of focal length 25 cm. The power of combination in diopter is
a.  - 1.5
b. + 1.5
c.  + 6.5
d.  + 6.67

25. Magnification at least distance of distinct vision of a simple microscope having its focal length 5 cm  is
a.  4
b. 5
c. 6
d. 7

26. If a convex lens of focal length f is cut into two identical halves along the lens diameter what is the focal length of each piece?
a. Half
b. Double
c. Same
d. Thrice

27. How is the information transmitted into an optical fiber?
a. It is converted into light signals that travel at high speed through fiber
b. It is converted into electrical signals that travel through wires
c. It is imprinted onto glass beads that roll at high speed through the glass fiber
d. It is converted into electrical signals that continuously bounce off the fiber wall

28. What purpose does the eyepiece of a microscope serve?
a. It further magnifies the image formed by the objective lens
b. It helps direct light towards the objective lens
c. It reduces the image formed by the objevtive lens so the image fits in the field of view
d. It illuminates objects placed on a transparent glass side

29. Resolution in a microscope is primarily determined by which lens
a. Ocular
b. Projector
c. Objective
d. Condenser

30. When a ray of light enters a glass slab from air
a. Its wavelength increases
b. Neither its wavelength nor its frequency changes
c. Its frequency changes
 d. Its wavelength decreases

31. A converging lens is used to form an image on a screen. When the upper half of the lens is covered by an opaque screen
a. Half the image will disappears
b. Complete image will be formed
c. Intensity of image will increase
d. Intensity of image will decrease

32. How many slits would a diffraction grating need to be able to resolve two wavelengths 500.0 nm and 500.1 nm in the second order
a. 5000
b. 50,000
c. 2500
d. 25,000

33. A man who cannot see clearly beyond 10 m wants to see starts clearly. He should use a lens of power (in diopter)
a. 10
b. - 10
c. - 1
d. - 0.1

34. When the length of microscope tube increases its magnifying power
a. Increases
b. Decreases
c. Does not change
d. Many decreases and increases

35. A double convex lens of refractive index m2 is immersed in a liquid of refractive index m1. This lens will act as converging lens. if
a. m1>m2
b. m2>m1
c. m1=m2
d. m1=m2=0

36. A cannot engine converts 1/5 of the heat, which it absorbs from source,into work. When the temperature of sink is reduced by 10000C its efficiency is doubled. The temperature of the source is
a. 400K
b. 500K
c. 450K
d. 700K


  1. 1.a

    1. 1st qn can it be d


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