Question # 1

The process of pair production will take place if the energy of photon is greater than.

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0.21 MeV

0.51 MeV

1.51 MeV

1.21 MeV

The back ground radiation in the atmosphere on the average is

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0.5 Sv per year

1.0 Sv per year

1.5 Sv per year

2.0 Sv per year

In which of the following controlled nuclear chain reaction is used to liberate energy.

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Nuclear bomb

Atomic bomb

Hydrogen bomb

Nuclear reactor

Which of the following phenomenon is explained by the tunnel efffect.

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Alpha decay

Beta decay

Gama decay

Radioactivity

The total number nucleons in a nucleus are called.

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Mass number

Atomic number

Neutron number

Isotopes

Which of the following is required for maintaining sustained chain reaction.

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Neutrons

Protons

Electrons

Photons

Which temperature is required for the fusion of two nuclides.

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10⁶ K

10⁷K

10⁸K

10 ⁹ K

Which of the following has the highest relative biological effectiveness or the quality factor.

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X rays and Gama rays

Electrons

Photons

Alpha particles

The emission of Beta particle from protonium -218 results in the formation of.

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Protactinium -231

Thorium -232

Astatine -218

Radon -222

In heavy atims the electrons are assumed to be arranged in.

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Elliptical shells

Inner shells

Concentric shells

Outer shells

Radius of the Bother's orbit is r the radius of second orbit will be.

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2 r

3 r

4 r

8 r

The maximum energy of emitted photoelectron is measured by

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the largest potential difference they can traverse

The current they produce

The potential difference they produce

The speed with they emerge

There are how many modes of operations of a BJT.

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2

3

4

5

Which experiment is a demonstration that matter and energy can display properties of both waves and particles.

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young's double slit experiment

Division germier experiment

Heisenberg's uncertainty experiment

Stern Gerlach experiment

At room temperature the potential difference between the two sides of depletion region for silicon is of the order of.

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0.3 v

0.5 V

0.7 V

0.9 V

The total energy of an electron in an orbit around the nucleus is.

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Zero

Unity

Infinity

Negative

48 days after the receipt the amount of iodine -131 left behind is only.

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0.1325 g

0.2135 g

0.3125 g

0.1235 g

The angular speed of an electron in the nth orbit of Bohr's hydrogen atom is.

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Directly proportional to n

Directly proportional to n2

Inversely proportional to n

Inversely proportional to n2

The Compton effect in X-rays proves that

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Electrons have wave property

x-rays have wave properly

X-rays have particle characteristics

Electrons cannot exist

The path of electron in Rutherford atomic model according to classical theory a.

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Parabolic

Straight line

Spiral

Circular

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