Tag: physics

Quizzes (598) Questions (13441)

Questions Related to physics

Multiple choice physics current electricity and magnetism electric cells and batteries

While making a battery ___________  of a cell is connected to ________ of other cell.

  1. negative terminal , negative terminal

  2. positive terminal , negative terminal

  3. positive terminal , positive terminal

  4. neutral terminal ,negative terminal
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

While making a battery, negative end of battery is connected to positive terminal of other cell and so on.


Answer-(B)

Multiple choice physics electricity electric cells and batteries

When the two terminals of a battery are connected directly with a wire then:

  1. More electrical energy is stored in the cell

  2. The chemicals get used up very fast

  3. No current flows in the wire

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
When the two terminals of a battery are connected directly with a wire there will be a low resistance path for the current to flow. The wire will get heated a little bit (depends on the diameter of the wire less the diameter more heat) and the battery will be quickly discharged. During depletion, it may become very hot, emit gasses, and possibly explode. The shorting wires will draw heavy current that may melt the wire or even cause them to soften and break.
Multiple choice physics electricity electric cells and batteries

Many devices such as.............. use batteries-

  1. Torches

  2. Transistors, toys

  3. T.V. remote controls

  4. All of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Many devices such as----------------use battery 

Torches 
Transistors, toys 
T.V remote controls
All of these use batteries.

Multiple choice applications of gauss's law coulomb's law physics

A charge is kept at the centre of a shell. Shell has charge Q uniformally distibuted over its surface and radius R. The force on the central charge due to the shell is :

  1. towards left

  2. towards right

  3. upward

  4. zero
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Electric field at the centre of shell is zero when charge is uniformally distributed over surface of shell . 

Hence the force on the charge at the centre is zero.

Multiple choice applications of gauss's law coulomb's law physics

A hollow conducting sphere of charge does not have electric field at

  1. outer point

  2. interior point
  3. beyond $2m$
  4. beyond $100m$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$E=0$, at any point inside the sphere

Multiple choice applications of gauss's law coulomb's law physics

The rupture of air medium occurs at $E=3\times 10^6 \ V/m$. The maximum charge that can be given to a sphere of diameter $5 \ m$ will be (in coulomb):

  1. $2\times 10^{-2}$
  2. $2\times 10^{-3}$
  3. $2\times 10^{-4}$
  4. $2\times 10^{-5}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Given, $E _o= 3 \times 10^6 \ V/m;$  Diameter of sphere $= 5 \ m$

Electric field on the surface of the sphere $= \cfrac {KQ}{R^2}$

$E _o= \cfrac {KQ}{R^2}$

$Q= \cfrac {R^2E^o}{K}= \cfrac {6.25 \times 3 \times 10^6}{9 \times 10^9}$

$= 2 \times 10^{-3}\ C$

Multiple choice applications of gauss's law coulomb's law physics

A spherical shell of mass $m$ and radius $R$ filled completely with a liquid of same mass and set to rotate about a vertical axis through its centre has a moment of inertia ${I _1}$ about the axis$.$ The liquid starts leaking out of the hole at the buttom$.$ If moment of inertia of the system is ${I _2}$ when the shell is half filled and ${I _3}$ is the moment of inertia when entire water drained off$.$ then $:$

  1. $\dfrac{{{I _1}}}{{{I _2}}} \approx 1.5$
  2. $\dfrac{{{I _{ _1}}}}{{{I _2}}} \approx 0.67$
  3. $\dfrac{{{I _1}}}{{{I _3}}} \approx 1.6$
  4. $\dfrac{{{I _2}}}{{{I _3}}} \approx 1.4$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Moment of inertia of a shell$,$ ${I _3} = \frac{2}{3}M{R^2}$ 

Moment of inertia of a completely filled sphere$,$ ${I _1} = \frac{2}{3}M{R^2} + \frac{2}{5}M{R^2} = \frac{{16}}{{15}}M{R^2}$ 
Moment of inertia of a half sphere$,$ ${I _2} = \frac{2}{3}M{R^2} + \frac{2}{5}\frac{M}{2}{R^2} = \frac{{26}}{{30}}M{R^2}$
Hence,
option $(C)$is correct answer.

Multiple choice applications of gauss's law coulomb's law physics

A positive charge q is placed in a spherical cavity made in a positively charged sphere. The centres of sphere cavity are displaced by a small distance $\overrightarrow l $. Force on charge q is:

  1. in the direction parallel to vector $\overrightarrow l $

  2. in radial direction

  3. in a direction which depends on the magnitude of charge density in sphere

  4. direction can not be determined.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Inside a uniformly charged sphere, the electric field is uniform and proportional to the displacement vector between the centers of the sphere and the cavity. Therefore, the force on a positive charge placed in the cavity is directed parallel to the displacement vector l.

Multiple choice applications of gauss's law coulomb's law physics

At all points inside a uniform spherical shell -

  1. gravitational intensity and gravitational potential both are zero

  2. gravitational intensity and gravitational potential both are non- zero

  3. gravitational intensity is non- zero and gravitational potential both are zero

  4. gravitational intensity is zero and gravitational potential both are non-zero
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Gravity Force Inside a Spherical Shell. The net gravitational force on a point mass inside a spherical shell of mass is identically zero! Physically, this is a very important result because any spherically symmetric mass distribution outside the position of the test mass m can be build up as a series of such shells