Radioactivity

Q. 16 gm sample of a radioactive element is taken from Bombay to Delhi in 2 hour and it was found that 1 gm of the element remained (undisintegrated). Half life of the element is

1. $2hour$
2. $1hour$
   
3. $\frac{1}{2}hour$
4. $\frac{1}{4}hour$

Q.

What are the properties of ultraviolet waves?

Q.

What is the use of radioisotopes in the medical field?

Q.

State four properties of ultraviolet radiations.

Q.

What are the important precaution that should be taken while handling radioactive materials?

Q.

What is a real life example of radiation?

Q.

Define alpha particles and give some examples of it.

Q.

How is alpha decay used in everyday life?

Q.

How are the underground leakages of water pipes detected?

Q.

Radioactive radiations are of three types out of these one radiation remains unaffected by an electric or magnetic fields. Name this radiation.

1. Gamma Radiation

2. Beta Radiation

3. Alpha Radiation

4. Positron Radiation

Q. 16 gm sample of a radioactive element is taken from Bombay to Delhi in 2 hour and it was found that 1 gm of the element remained (undisintegrated). Half life of the element is

1. $2hour$
2. $1hour$
   
3. $\frac{1}{2}hour$
4. $\frac{1}{4}hour$

Q.

Define Hawking Radiation.

Q. A hydrogen bomb works on the principle of the nuclear fusion reaction.

1. True
2. False

Q.

In which radioactive disintegration, the neutron dissociates into proton and electron?

1. $\alpha -emission$

2. $\beta -emission$

3. $\gamma -emission$

4. $Positronemission$

Q.

Write two applications of each of the following in day-to-day life: Radiation

Q.

Why are alpha particles emitted?

Q.

Does $UV$ light kill Blue-Green Algae?

Q.

State two uses of radioactive substances.

Q.

Give two precautions that should be taken while handling radioactive material.

Q.

Match the following for a pair of protons:
1. Electrostatic Force I. Attractive
2. Nuclear Force II. Repulsive

1. 1-I, 2-II

2. 1-I, 2-I

3. 1-II, 2-II

4. 1-II, 2-I

Q. Which of the following are the harmful effects of radiation?

1. Genetic defects
2. Cancers like leukaemia
3. Diarrhoea and sore throat
4. Increased lifespan

Q.

Radioactive materials as an alternative source of energy must be used wisely. Give reasons to justify this statement.

Q.

Radioactivity is a nuclear phenomenon. Comment on this statement.

Q.

Give two important precautions that should be taken while handling radioactive materials.

Q. Which of the following statements is/are wrong regarding the safety measures against the harmful effects of radioactivity?

1. Radioactive waste should be disposed far away from populated areas.
2. Radioactive material should be stored in plastic or copper containers.
3. People working in nuclear power plant should not be tested for radiation exposure frequently.
4. Nuclear reactors should be enclosed in thick lead and concrete walls.

Q. Pick the correct statements regarding the uses of radioactivity.

1. β-particles are used as projectiles in nuclear reactors.
2. Radioactive tracers are used in detecting blood clots.
3. $136C$ is used to estimate the age of fossils.
4. Radiation is used to remove unwanted accumulated electric charge in machinery.

Q.

Suppose you are in an empty room which only contains UV-light. Will you be able to see walls? What is the range of wavelength of light we can see?

Q.

Which of the following was a recent major nuclear accident?

1. Three mile nuclear accident

2. Chernobyl nuclear accident

3. Fukushima nuclear accident

4. Lucens reactor accident

Q.

An isotope of Uranium is given as ${}_{92}{X}^{235}$. Which of the following option/s is/are correct?

1. Number of neutrons is 235

2. Number of neutrons is 143

3. Number of electrons is 92

4. Mass number is 92

Q. Explain briefly why :
(a) $\alpha -particles$ cannot travel through the air for a long distance?
(b) $\gamma -radiations$ can travel through the air for a long distance?
[5 MARKS]