(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.

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

(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:

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

Give two differences between nuclear fission and nuclear fusion.

A radioactive element is kept in an evacuated chamber. The rate of radioactive emission will: (a) decrease (b) increase (c) remain unchanged (d) depend on the temperature

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.

Curium is a radioactive element with the symbol named in honour of Madam Curie. The graph of number of protons vs number of neutrons for some elements is shown below: (a) Which point on the graph indicates the element Cm? (b) Which point on the graph indicates daughter nucleus after Cm undergoes radioactive decay of 1α followed by 2β? (c) State the mass number of the daughter nucleus.

Complete the following by choosing the correct answers from the bracket: (a) In uniform circular motion the centrifugal force acts ............... [towards the centre/away from the centre/along the tangential direction]. (b) Refractive index of a medium is independent of ............... [temperature/angle of incidence/wavelength of light]. (c) Heat absorbed during change of phase depends on ............... [mass/change in temperature/specific heat capacity] of the substance. (d) Emf of a cell is ............... [greater than/less than/equal to] the terminal voltage when the cell is in open circuit. (e) In a step-up transformer the turns ratio is ............... [more than 1/less than 1/equal to 1]. (f) The nuclear radiation with lowest ionising power is ............... [α/β/γ].

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