A radioactive nucleus containing 128 nucleons emits a β-particle. After β-emission the number of nucleons present in the nucleus will be: (a) 128 (b) 129 (c) 124 (d) 127

(a) In the following atoms, which one is a radioisotope? Give one use of it. O-16, C-14, N-14, He-4 (b) Name the class of the lever shown in the picture below:

(a) Complete the following radioactive reaction: (b) Uranium is available in two forms U-235 and U-238. Which of the two isotopes of Uranium is more fissionable?

Copy and complete the nuclear reaction by filling in the blanks.

Which of the following radiations suffer maximum deflection in a magnetic field? (a) Alpha radiations (b) Beta radiations (c) Gamma radiations (d) X-radiations

A radioactive element P emits one α-particle and transforms to a new element Q. What will be the position of the element Q in the periodic table? (a) One group to the left of P (b) One group to the right of P (c) Two groups to the right of P (d) Two groups to the left of P

A lithium atom has 3 electrons, 3 protons and 4 neutrons. Its mass number is: (a) 3 (b) 4 (c) 7 (d) 10

(a) When does the nucleus of an atom tend to become radioactive? (b) Name a single pulley in which displacement of load and effort is not the same. (c) State one advantage of this pulley.

(a) Which nuclear radiation will travel undeviated in an electric field? (b) How can one stop the radiations escaping from a nuclear reactor in a nuclear power plant? (c) Name one internal source of background radiations.

(a) Complete the following nuclear changes: (b) Name the nuclear radiation which has the highest ionizing power.

How is the radioactivity of a radio isotope affected if it undergoes a chemical change? Give a reason for your answer.

Study the reaction given below and answer the questions that follow: (a) Name the process depicted in the reaction. (b) What is the value of X represented by the mass number of the intermediate uranium nucleus? (c) Identify Y, the missing product of the reaction.