Mock Test-2 (Paper-1) (Question 51-100)

Total Questions: 50

21. Ultrasonic waves are used for stirring liquid solutions because they

Correct Answer: (c) can produce perfectly homogeneous solution
Solution:Ultrasonic waves can produce perfectly homogeneous solution. It is used in homogenising milk constituents, etc.

22. The sun is seen before the actual sunrise because of ...... .

Correct Answer: (a) reflection

23. Choose the incorrect statement?

Correct Answer: (c) For a convex lens, if the object is placed between the focus and optical centre then the image formed will be diminished
Solution:
  • Light from sun takes nearly eight minutes 20 seconds to come to earth.
  • The image formed by a convex lens when the object is placed between the focus and the optical centre is virtual and magnified.
  • Cinematography makes use of persistence of vision. Persistence of vision is the ability of an eye to continue to see the image of an object for a very short duration even after the removal of the object.

24. Which of the following electromagnetic wave has the longest wavelength?

Correct Answer: (a) Infra red rays
Solution:Higher the wavelength, lower is the energy of the electron magnetic wave.

25. A coil and a bulb are connected in series with a 5V d.c. source. When a soft iron core is inserted in the coil, the light emerging from the bulb -

Correct Answer: (c) Remains the same
Solution:The resistance offered by the coil due to DC current remain zero hence there be no effect on light emerging from bulb

26. The most familiar form of radiant energy in sunlight that causes tanning and sun burning of human skin, is called

Correct Answer: (a) ultraviolet radiation
Solution:The tanning and sun burning of human skin is due to the harmful ultraviolet radiation from the sun.

27. The phenomenon of mirage occurs due to which one of the following?

Correct Answer: (d) Total internal reflection of light
Solution:Total internal reflection is responsible for mirage formation in deserts.

28. 'Freon' used as refrigerants is chemically known as

Correct Answer: (c) chlorofluoro hydrocarbon
Solution:Chlorofluoro carbon (CF₂C₁₂) is also known as freon. It is used as refrigerants in refrigerators and air conditions. It is also used as propellant in aerosols and foams.

29. Which one of the following is used as a mordant in dyeing and tanning industry?

Correct Answer: (d) Magnesium sulphate
Solution:Magnesium sulphate (MgSO₄) is used as a mordant in dyeing and tanning industry.

30. Which one among the following nontoxic gases helps in formation of enzymes which ripen fruit?

Correct Answer: (a) Acetylene
Solution:Acetylene is the nontoxic gases that help in formation of enzymes which riper fruit. Ripening is a process in fruits causes them to become more palatable.