Practice Gk questions test 3 - general science mcq Online Quiz (set-1) For All Competitive Exams

Q-1)   Which part of the solar cooker is responsible for green house effect?

(a)

(b)

(c)

(d)

Q-2)   Chadwick was awarded the 1935 nobel prize in physics for his discovery of the

(a)

(b)

(c)

(d)

Q-3)   Consider the following statements :
  1. Collation is a process of sorting at receiving end
  2. Encoding of signal is required for modulation at transmitting end
  3. Long wave broadcast transmitter are used for temperate countries
Which of the above statements are correct?

(a)

(b)

(c)

(d)

Q-4)   Which of the following statement is/are the applications of photovoltaic cells?
  1. They are used to detect opacity of solids, defects in materials.
  2. They are used to switch on and off the street lights automatically
  3. They are used to compare illuminating power of two sources.
  4. To control temperature in furnaces and chemical reactions

(a)

(b)

(c)

(d)

Q-5)   Consider the following statements:
  1. A geostationary satellite is at an approximate height of 10,000 km.
  2. FM transmission of music is of very good quality because the atmospheric or man-made noises which are generally frequency variations can do little harm.
Which of the statement(s) given above is/are correct?

(a)

(b)

(c)

(d)

Explanation:

The geostationary satellite is a satellite having a time period of 24 hours. Using this time period, the height of the satellite comes out to be approximately 35,800 km.

FM broadcasting is a broadcast technology pioneered by Edwin Howard Armstrong that uses frequency modulation (FM) to provide high-fidelity sound over broadcast radio. FM transmission is quite immune to noise as compared to AM transmission.

Noise is a form of amplitude variations in the transmitted signal due to atmosphere, industries, etc.

Q-6)   If an a-particle is projected normally through a uniform magnetic field, then the path of the a-particle inside the field will be

(a)

(b)

(c)

(d)

Q-7)   Consider the following statements: In a nuclear reactor, self-sustained chain reaction is possible, because:
  1. More neutrons are released in each of the fission reactions.
  2. The neutrons immediately take part in the fission process.
  3. The fast neutrons are slowed down by graphite.
  4. Every neutron released in the fission reaction initiates further fission.
Which of the statements given above are correct?

(a)

(b)

(c)

(d)

Explanation:

A nuclear reactor is a device to initiate and control a sustained nuclear chain reaction. The most common use of nuclear reactors is for the generation of electrical power and for the power in some ships.

In every fission reaction in which uranium nuclei splits up to give smaller nuclei three more neutrons are produced which further results into splitting of heavy uranium nuclei and more number of neutrons will be produced.

Thus, statement, 1 & 2 are correct.

In nuclear reactor all the neutrons produced can not take part in fission reaction, else reaction can turn out extremely violent. Thus, graphite rods are used as a control rods to slow down the speed of fast moving neutrons. Thus, statement 3 is also correct.

Q-8)   Telephony is an example of ________ mode of communication

(a)

(b)

(c)

(d)

Explanation:

Q-9)   Which of the following statements is/are correct ?
  1. Pure Si doped with trivalent impurities gives a p-type semiconductor
  2. Majority carriers in a n-type semiconductor are holes
  3. Minority carriers in a p-type semiconductor are electrons
  4. The resistance of intrinsic semiconductor decreases with increase of temperature

(a)

(b)

(c)

(d)

Q-10)   Which of the following does NOT allow harmful ultraviolet radiations from the sun to reach the earth?

(a)

(b)

(c)

(d)

Explanation: