Tag: physics

Questions Related to physics

Which one does not work on principles of resonance?

physics free, damped and forced oscillations resonance: examples and uses resonance oscillatory motion

  1. T.V

  2. Radio

  3. Microwave oven

  4. Bulb

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Correct Option: D
Explanation:

Resonance in an electrical circuit is a phenomenon in which the inductive reactance and the capacitive reactance become equal and cancel each other.

As a result, the impedance of the circuit becomes the least and maximum current flows through the circuit. This happens only at a particular frequency of the AC power supply, known as resonant frequency. 
All the devices except bulb work on this principle. The circuit in them is tuned in order to make their resonant frequency matching with the desired one. This is done by adjusting the values of the inductor or the capacitor.
In a bulb, there is only pure resistance and no reactive component. There is no question of resonance.

In a resonance column experiment, the first resonance is obtained when the level of the water in tube is $20 cm$ from the open end. Resonance will also be obtained when the water level is at a distance of

physics free, damped and forced oscillations resonance: examples and uses resonance oscillatory motion

  1. $40 cm$ from the open end.

  2. $60 cm$ from the open end.

  3. $80 cm$ from the open end.

  4. data insufficient.

Show answer
Correct Option: B
Explanation:

In a closed pipe : length of the pipe is length of the air column in fundamental.

$\dfrac { \lambda  }{ 4 } =20cm$ 
${ 2 }^{ nd }$ harmonic resonance $=\dfrac { 3\lambda  }{ 4 } =3\times 20=60cm$

$\therefore $  Option (B) is correct.

Assertion : In the ideal case of zero damping, the amplitude of simple harmonic motion at resonance is infinite.
Reason : All real systems have some damping.

physics free, damped and forced oscillations resonance: examples and uses resonance oscillatory motion

  1. If both assertion and reason are true and reason is the correct explanation of assertion.

  2. If both assertion and reason are true and reason is not the correct explanation of assertion.

  3. If assertion is true but reason is false.

  4. If both assertion and reason are false.

Show answer
Correct Option: B
Explanation:

If there was no damping in the swing, the swing would move with larger and larger amplitudes. However, most physical systems have damping, which limits the size of the amplitude. If you don not have damping the amplitudes will go to infinity.

So, Assertion and reason both are true. But reason is not current explanation for the assertion.

Identify the correct statement/statements :
a) Radiation causes genetic mutation
b) Restriction in blood circulation can be detected using radio-iodine
c) Hydrocarbon plastics are used as moderators in a nuclear reactor
d) The damage caused due to $\alpha$-radiation is small due to its small penetrating power

physics energy production hazards and safety measures of radiations harmful effects and safety precautions for radiations nuclear physics

  1. a,b,c

  2. a,c,d

  3. b,c,d

  4. a,b,d

Show answer
Correct Option: B
Explanation:

a]  is true
c]  fast neutrons produced collides with the particles of
     moderator to slow down
d]  penetration power of $\alpha$ particle is smallest

PPE is 

physics energy production hazards and safety measures of radiations harmful effects and safety precautions for radiations nuclear physics

  1. equipments for handling radioactive waste.

  2. equipments for handling radioactive substance.

  3. Personal Protective Equipment

  4. none of the above

Show answer
Correct Option: C
Explanation:

PPE is personal protective equipment refers to protective clothing, goggles, helmets or other garments required to protect the wearer's body from injury and infection. The purpose of PPE is to reduce employee exposure to hazards.

Which of the following is followed while handling the radioactive materials?

physics energy production hazards and safety measures of radiations harmful effects and safety precautions for radiations nuclear physics

  1. Wearing protective clothing.

  2. Keeping as far away as is practicable - for example, by using tongskeeping

  3. Keeping radioactive materials in lead-lined containers,

  4. All of the above.

Show answer
Correct Option: D
Explanation:

D

While handling with radioactive materials we must wear protective clothing and keep it as far as possible. The radioactive materials must be in a lead lined contained because the gamma rays emitting from the radioactive material can be prevented using lead lined materials only. 

Why should a radioactive substance not be touched by hand?

physics energy production hazards and safety measures of radiations harmful effects and safety precautions for radiations nuclear physics

  1. It is hot

  2. It is very cold

  3. It can harm our body

  4. None of the above

Show answer
Correct Option: C
Explanation:
Because it emits a lot of harmful radiations that penetrate our body and cause serious damage to the cells.

In the process of Radio active decay the correct example is _____.

physics energy production hazards and safety measures of radiations harmful effects and safety precautions for radiations nuclear physics

  1. $ _6C^{14} \xrightarrow[of \,\propto \,particle]{emission} { _7C^{15}}$

  2. $ _6C^{14} \xrightarrow[of \,\propto \,particle]{emission} { _7N^{15}} + 1e$

  3. $ _6C^{14} \xrightarrow[of \,\propto \,particle]{Absorption} { _7N^{15}}$

  4. None of these

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Correct Option: D

What safety precautions that you would take while handling the radioactive substances?

physics energy production hazards and safety measures of radiations harmful effects and safety precautions for radiations nuclear physics

  1. Always wear gloves

  2. Don't wear gloves

  3. Wear a proper coat provided in lab

  4. None of the above

Show answer
Correct Option: A,C
Explanation:
While handling the radioactive substances,
$\rightarrow$ Always wear gloves.
$\rightarrow$ Wear proper coats provided in the labs.
$\rightarrow$ Keep personal items like handbags, lunchboxes etc. outside the lab.

Two radioactive samples $A$ and $B$ have half lives ${T} _{1}\ and {T} _{2}\left ({T} _{1}>{T} _{2}\right)$ respectively. At $t = 0$, the activity of $B$ was twice the activity of $A$. Their activity will become equal after a time 

physics energy production hazards and safety measures of radiations harmful effects and safety precautions for radiations nuclear physics

  1. $\dfrac {{T} _{1}{T} _{2}}{{T} _{1}-{T} _{2}}$

  2. $\dfrac {{T} _{1}-{T} _{2}}{2}$

  3. $\dfrac {{T} _{1}+{T} _{2}}{2}$

  4. $\dfrac {{T} _{1}{T} _{2}}{{T} _{1}+{T} _{2}}$

Show answer
Correct Option: A