Physics/

The becquerel  is the SI derived unit of radioactivity. One becquerel is defined as the activity of a quantity of radioactive material in which one nucleus decays per second.

Antoine Henri Becquerel the first person to discover evidence of radioactivity

10. Radio-activity was first discovered by (a)  Pasteur(b)Newton (c)Watson (d)Marie Curie

And; Watson

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8.      8. A  block of ice is floating in a glass containing water. When the ice melts completely, .. of the water in the glass will (Jto-lice Bihar 2013)

a)      Rise

b)      Fall

c)       Not chage

d)      None of these

Ans:c

9.    9. How can boiling point of a liquid be reduced?

a)By adding a soil of lower melting point

b) by dissolving a soluble solid in it

c) by increasing the pressure on the liquid

d) by decreasing the pressure of  the liquid

     ans: d

1    10.  Electromagnetic  radiation with maximum wavelength is  (Jto-lice Bihar 2013)

a)      Ultraviolet

b)      Radio waves

c)       X-rays

d)      Infrared

Ans:b

12.   The process of sudden cooling is known as  (Jto-lice Bihar 2013)

a)      Annealing

b)      Diffusing

c)       Quenching

d)      Seimentation

Ans: c

1

14.   With respect to speed and velocity  which of the following is true?

a     (a)  Speed and velocity are always equal

b     (b) Speed is always less than velocity

       (c) Velocity is always smaller than or equal to speed

d     (d) Speed is always smaller than or equal to velocity

Ans: c

7.  Which of the following is a vector quantity? (Jto-lice Bihar 2013)

a)      Momentum

b)      Pressure

c)       Energy

d)      Work

Ans: a