Tag: physics

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Questions Related to physics

Multiple choice free, damped and forced oscillations free, forced and damped oscillations oscillations oscillation and waves physics

The motion of a vehicle suspension system just after the vehicle encounters a pothole is an example of 

  1. natural vibration

  2. damped vibration

  3. forced vibration

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The motion of a vehicle suspension system just after the vehicle encounters a pothole is an example of natural vibration. When suspension system encounters a pothole it is disturbed from its equilibrium position after that an oscillatory motion generates inside it to take it back its initial position but there is no external force which maintains that oscillatory motion.

Multiple choice free, damped and forced oscillations free, forced and damped oscillations oscillations oscillation and waves physics

Assertion : A child in a garden swing periodically presses his feet against the ground to maintain the oscillations.
Reason : Then all free oscillations eventually die out because of the ever present damping force.

  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.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The free oscillation of a body or system is due to its own natural frequency and under no external influence. But to carry out it continuously, the external impulse is needed. The child is doing this by pressing the ground.

Obviously, in the absence of such external impulse or force, free oscillations will die soon due to other negative forces i.e. damping forces.

Therefore assertion and reason both are correct and the reason is the correct explanation of assertion.

 

Option A is correct.

Multiple choice free, damped and forced oscillations free, forced and damped oscillations oscillations oscillation and waves physics

A linear harmonic oscillator of force constant $2 \times$10$^{6}$Nm$^{-1}$ and amplitude 0.01 m has a total mechanical energy of 160 J. Its

  1. maximum potential energy is 100 J

  2. maximum kinetic energy is 100 J

  3. maximum potential energy is 160 J

  4. minimum potential energy is zero.
Reveal answer Fill a bubble to check yourself
B,C Correct answer
Explanation

As, we know total mechanical energy $=$ maximum potential energy

$\therefore \quad ATQ.T.E=160J\Rightarrow Max.P.E.=160J$
$\Rightarrow$  Statement (C) is correct.
Also, for maximum kinetic energy, we know,
$K.E.=\dfrac { 1 }{ 2 } K\left( { x } _{ m }^{ 2 } \right) $
where ${ x } _{ m }=\left( 0.01 \right) m\quad & \quad K=2\times { 10 }^{ 6 }{ Nm }^{ -1 }$
$\Rightarrow K.E.=\left( \dfrac { 1 }{ 2 }  \right) \left( 2\times { 1 }0^{ 6 } \right) { \left( 0.01 \right)  }^{ 2 }=100J$
$\Rightarrow$  Statement (B) is the correct answer.

Multiple choice physics electrical conductivity of liquids does liquid conduct electricity? liquids conduct electricity do liquids conduct electricity?

A tester is used to check the conduction of electricity through two liquids, labeled $A$ and $B$. It is found that the bulb of the tester glows brightly for liquid $A$ while it glows very dimly for liquid $B$. You would conclude that:

  1. liquid $A$ is a better conductor than liquid $B$
  2. liquid $B$ is a better conductor than liquid $A$

  3. both liquids are equally conducting

  4. conducting properties of liquid cannot be compared in this manner
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The amount of current flowing through a conducting solution depends on the conductivity of the solution. More the conductivity, more current passes through the solution and vice-versa. Hence, the conductivity of liquid $A$ is more than the conductivity of liquid $B$.

Multiple choice physics electrical conductivity of liquids does liquid conduct electricity? liquids conduct electricity do liquids conduct electricity?

Charging a body by simply touching it is called ........ .

  1. Conduction

  2. Charging by frictionc

  3. Induction

  4. All the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Transfer of either heat or charge or an physical qty by touching is called conduction while rubbing against each other is know as friction. And charging by induction does not involve any contact with the surface whatever so.

Charging by simply touching is called conduction.

Multiple choice physics electrical conductivity of liquids does liquid conduct electricity? liquids conduct electricity do liquids conduct electricity?

A long parallel straight conductors carry $i _{1}$ and $i _{2}(i _{1} > i _{2})$. When the currents are in same direction, the magnetic field at a point midway between the wires is $20 \mu T$. If the direction of $i _{2}$ is reversed, the field becomes $50 \mu T.$ The ratio of the current $i _{1}/ i _{2}$ is:

  1. $\dfrac{5}{2}$
  2. $\dfrac{7}{3}$
  3. $\dfrac{4}{3}$
  4. $\dfrac{5}{3}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice physics electrical conductivity of liquids does liquid conduct electricity? liquids conduct electricity do liquids conduct electricity?

select the incorrect alternative:

  1. The charge gained by the uncharged body from a changed body due to conduction is of of the same nature of charge initially present on charged body

  2. the magnitude of charge increases with the increase in velocity of charge

  3. charge can not exist with out matter although matter can exist with out charge.

  4. Between two non-magnetic substances is true test of electrification ( electrification means body has net charge )
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Charge is an invariant quantity in special relativity; its magnitude does not change with velocity. Option C is also technically false as charge is a property of matter, but B is a more fundamental error regarding the definition of charge.