Tag: physics

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Multiple choice physics behaviour of perfect gas and kinetic theory of gases degree of freedom: law of equipartition of energy law of equipartition of energy law of equipartition of energy and mean free path

Relation between pressure ($P$) and energy density ($E$) of an ideal gas is-

  1. $P=2/3E$

  2. $P=3/2E$

  3. $P=3/5E$

  4. $P=E$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Kinetic energy $=\dfrac{1}{2}{ MV } _{ rms }$
$\Rightarrow \dfrac{1}{2}M\left( \dfrac { 3RT }{ M }  \right) $        $[M=$ molar mass,$ { V } _{ rms }=\sqrt { \dfrac { 3KT }{ { m } }  } =\sqrt { \dfrac { 3RT }{ M }  } ]$
$=\dfrac{3}{2}RT$
$\Rightarrow K.E=\dfrac{3}{2}PV$          $[PV=RT]$
$\Rightarrow \dfrac{K.E}{V}=\dfrac{3}{2}P$
$\Rightarrow E=\dfrac{3P}{2}$        $E=$ Energy density.
Hence, the answer is $P=\dfrac{2}{3}E.$
Multiple choice physics behaviour of perfect gas and kinetic theory of gases degree of freedom: law of equipartition of energy law of equipartition of energy law of equipartition of energy and mean free path

A vessel of volume $0.3 \ { { m }^{ 3 } }$ contains Helium at $20.0$. The average kinetic energy per molecule for the gas is:

  1. $6.07\times { 10 }^{ -21 }J$

  2. $7.3\times { 10 }^{ 3 }J$

  3. $14.6\times { 10 }^{ 3 }J$

  4. $12.14\times { 10 }^{ -21 }J$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Given temperature of gas $=20°C$
                                            $=293K$
$\Rightarrow$ Average translational kinetic energy $=\dfrac{3}{2}KT$
                                                                   $=\dfrac{3}{2}\times1.38\times10^{-23}\times293$
                                                                   $=6.07\times10^{-21}J$
Hence, the answer is $6.07\times10^{-21}J.$
Multiple choice physics science in daily life inventions and inventors in science scientists indian scientist: biography and achievements

Light pollution is caused when

  1. the ozone layer is damaged

  2. too much of light sources are used unnecessarily

  3. light sources pointing up to the sky rather than down to the earth

  4. sources of light are polluted
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Light pollution is primarily caused by the inefficient use of artificial light, specifically light that is directed upwards or sideways rather than being shielded and directed toward the ground where it is needed.

Multiple choice physics science in daily life inventions and inventors in science scientists indian scientist: biography and achievements

Which of the following scientists is known for his outstanding work in the genetic code?

  1. Satyendra Nath Bose

  2. Vikram Sarabhai

  3. Srinivasa Ramanujan

  4. Har Gobind Khorana
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Har Gobind Khorana was a biochemist who shared the 1968 Nobel Prize in Physiology or Medicine for his work on the interpretation of the genetic code and its function in protein synthesis.

Multiple choice physics science in daily life inventions and inventors in science scientists indian scientist: biography and achievements

Which Indian scientist is known for his crucial role in the development of Indias missile and nuclear weapons programmes?

  1. A. P. J. Abdul Kalam

  2. C. V. Raman

  3. Jagadish Chandra Bose

  4. Har Gobind Khorana
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A.P.J Abdul Kalam aka Missile Man, is known for hi crucial role in development of Indian missiles and nuclear weapons programmes.

Multiple choice physics electric current and its effects electric fuse electrical fuse and mcb fuse

......... suggested that the slips should be marked with load lines

  1. Samuel Plimsoll

  2. Einstein

  3. Newton

  4. Archimedes
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Fuse should be connected to live / phase wire o fthe circuit. If it is connected to neutral wire , the fuse will melt when excess current flows, but the appliance will still be connected to high potential through live wire. Thus, if a person touches the appliance, he receives shock. 
Hence, choice is (3) 

Multiple choice physics electric current and its effects electric fuse electrical fuse and mcb fuse

Fill in the blank-
An electric fuse works on the ______effect of current.

  1. heating

  2. magnetic

  3. chemical

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

Electric fuse work on the principal of heating effect of current . fuse wire is a wire of high resistance and low melting point. when very large current will pass through it, heat will be generated which will melt the fuse wire and break the circuit.By using electric fuses in home we can protect the home appliances from damaging by large amount of current.

Multiple choice physics electric current and its effects electric fuse electrical fuse and mcb fuse

A fuse wire is generally made of

  1. tin

  2. tin-lead alloy

  3. copper

  4. either (a) or (b) above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Fuse wire are used to save the home appliances from damagaing by large currents. so they are made up of such materials which have high resistance and low melting point so that they can melt down when unexpected amount of current is passed through.for this work either tin metal or tin-lead alloy will be appropriate.