Tag: physics

Questions Related to physics

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

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

  1. natural vibration

  2. damped vibration

  3. forced vibration

  4. None of these

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Correct Option: A
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.

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.

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

  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.

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Correct Option: A
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.

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

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

  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.

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Correct Option: B,C
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.

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:

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

  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

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Correct Option: A
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 $B$.

Solutions of acids and bases are generally :

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

  1. good conductors of electricity

  2. good conductors of heat

  3. good conductor of both heat and electricity

  4. none of the above

  5. all

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Correct Option: A
Explanation:

Solutions of acids and bases are generally good conductors of electricity.

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

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

  1. Conduction

  2. Charging by frictionc

  3. Induction

  4. All the above

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Correct Option: A
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.

How many times, the potential of big drop in comparison to small drops which is made of $8$ dropletes will be, if all the droplets are identical and having equal charge?

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

  1. $2$ times

  2. $4$ times

  3. $3$ times

  4. $8$ times

Show answer
Correct Option: D

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:

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

  1. $\dfrac{5}{2}$

  2. $\dfrac{7}{3}$

  3. $\dfrac{4}{3}$

  4. $\dfrac{5}{3}$

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Correct Option: A

Which of the following is not true about electric charge?

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

  1. Charge is a scalar quantity

  2. Charge on an isolated system is always conserved

  3. A particle having nonzero rest mass can have zero charge

  4. A particle having zero rest mass can have non zero charge

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Correct Option: A

select the incorrect alternative:

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

  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 )

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Correct Option: B