Tag: physics

Quizzes (598) Questions (13441)

Questions Related to physics

Multiple choice physics types of energy renewable and non-renewable resources renewable and non-renewable sources of energy substances, objects and energy

In a hydroelectric power plant ___ energy is converted into ____ energy.

  1. Chemical into electrical

  2. Chemical into mechanical

  3. Mechanical into electrical

  4. Electrical into mechanical
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In hydroelectric power plant following sequence of energy transformation take place, 

Kinetic energy of water to potential energy of water to mechanical energy of turbine to electric energy through generator.
So among the options given best possible answer is option C.

Multiple choice physics types of energy renewable and non-renewable resources renewable and non-renewable sources of energy substances, objects and energy

A single conservative force F(x) acts on a $1$ kg particle that moves along the x-axis. The potential energy U(x) is given by $U(x) = 10+(x-1)^2$ Where x is in meters. At x =$2$ m, the particle has a kinetic energy of $8$ Joules. Then the mechanical energy of particle is

  1. $18$ J
  2. $19$ J
  3. $20$ J
  4. $10$ J
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice physics types of energy renewable and non-renewable resources renewable and non-renewable sources of energy substances, objects and energy

If $484J$ of energy is spent in increasing the speed of a wheel from $60rpm$ to $360\ rpm$, the $M.I$ of the wheel is

  1. $1.6\ kg\ m^{2}$
  2. $0.3\ kg\ m^{2}$
  3. $0.7\ kg\ m^{2}$
  4. $1.2\ kg\ m^{2}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$\begin{array}{l} { \eta _{ 1 } }=60rpm=\dfrac { { 60 } }{ { 60 } } rps=1rps \ \therefore { w _{ 1 } }=2r{ \eta _{ 1 } }=2\pi  \ { \eta _{ 2 } }=\dfrac { { 360 } }{ { 60 } } rpm=6rps \ { w _{ 2 } }=2\pi { \eta _{ 2 } }=12\pi  \end{array}$

484 joule of energy is spent in increasing.
$\begin{array}{l} \frac { 1 }{ 2 } Iw _{ 2 }^{ 2 }-\dfrac { 1 }{ 2 } Iw _{ 1 }^{ 2 }=484 \ \dfrac { I }{ 2 } \left( { { w _{ 2 } }+{ w _{ 1 } } } \right) \left( { { w _{ 2 } }-{ w _{ 1 } } } \right) =484 \ \dfrac { I }{ 2 } \left( { 12\pi +2\pi  } \right) \left( { 12\pi -2\pi  } \right) =484 \ I\, \, 14\pi .10\pi =484 \ I=\dfrac { { 484\times 2 } }{ { 140\times { \pi ^{ 2 } } } } =\dfrac { { 484\times 2 } }{ { 140\times 9.86 } }  \ =0.7\, \, kg\, \, { m^{ 2 } } \end{array}$
Option C.

Multiple choice physics study of sound reverberation applications of reflection of sound multiple reflection of sound and reverberation applications of ultrasound

Why do we hear more clearly in a room with curtains than in a room without curtains?

  1. sound is absorbed by the curtains.

  2. less reverberation

  3. a and b

  4. none
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

We hear more clearly in a room with curtains than of that in a room without curtains because curtains act as a good sound absorbent. So, they absorb the sound produced in the room and thus, prevent unwanted echo of sound due to refraction. Otherwise, the inter lapping of sounds would be most undesirable as we won't be able to hear clearly.

Multiple choice physics study of sound reverberation applications of reflection of sound multiple reflection of sound and reverberation applications of ultrasound

_________ is a device which is based on multiple reflection and isused for sending amplified sound in a particular direction.

  1. Bulb horn

  2. Megaphone

  3. Ear trumpet

  4. all
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Megaphone is based on multiple reflection of sound. It is a horn shaped tube designed to send amplified sound in a particular direction. It is also called Loud hailer.

Multiple choice physics study of sound reverberation applications of reflection of sound multiple reflection of sound and reverberation applications of ultrasound

Which of the following device does not work on the multiple reflections of sound waves?

  1. stethoscope

  2. hydrophone

  3. soundboard

  4. megaphone
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Stethoscope is a medical diagnostic instrument based on multiple reflection of sound waves.
This is used by doctors for listening to the sounds produced inside the body.
Sound board is a concave rigid surface which is placed behind the speaker in a big hall so that his words can be heard clearly even by the people sitting away from the stage.