Physics - Electric Charges Fields - Quiz-1

Two charges each equal to 2μC are 0.5m apart. If both of them exist inside the vacuum, then the force between them is

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(1) 89 N
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(2) 44 N
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(3) 0.144 N
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(4) 3.144 N

A cylinder of radius R and length L is placed in a uniform electric field E parallel to the cylinder axis. The outward flux over the surface of the cylinder is given by:

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$2 {πR}^{2} E$
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$\frac{{πR}^{2} E}{2}$
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$2 πRLE$
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${πR}^{2} E$

The electric intensity due to an infinite cylinder of radius R and having charge q per unit length at a distance r(r > R) from its axis is

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Directly proportional to r²
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Directly proportional to r³
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Inversely proportional to r
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Inversely proportional to r²

The electric field in a certain region is acting radially outward and is given by E=Ar. A charge contained in a sphere of radius 'a' centered at the origin of the field will be given by

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$4 π \in_{o} A a^{2}$
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$π \in_{o} A a^{2}$
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$4 π \in_{o} A a^{3}$
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$\in_{o} A a^{2}$

An electric dipole is in unstable equilibrium in the uniform electric field. The angle between its dipole moment and the electric field is

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90 $°$
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120 $°$
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0 $°$
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180 $°$

A particle having charge $q_{1}$ exerts F electrostatic force on charge $q_{2}$ at rest. If a particle having charge $\frac{q_{1}}{4}$ is placed midway between the line joining the two charges $q_{1} and q_{2}$ then electrostatic force on $q_{2}$ due to $q_{1}$ will become/remain

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2F
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$\frac{F}{2}$
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F
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zero

A charge q is to be divided on two small conducting spheres. What should be the value of charges on the spheres so that when placed at a certain distance apart, the repulsive force between them is maximum?

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$\frac{q}{4} a n d \frac{3 q}{4}$
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$\frac{q}{2} a n d \frac{q}{2}$
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$\frac{q}{3} a n d \frac{q}{3}$
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$\frac{q}{4} a n d \frac{q}{4}$

An electric dipole of dipole moment p is placed in an electric field of intensity E such that angle between electric field and dipole moment is $θ$ . Assuming that the potential energy of the dipole is zero when $θ = 0 °$ , the potential energy of the dipole will be

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-pE cos $θ$
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pE(1-cos $θ$ )
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pE(cos $θ$ -1)
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-2pE(cos $θ$ -1)

The electrostatic field due to a charged conductor just outside the conductor is

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zero and parallel to the surface at every point inside the conductor
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zero and is normal to the surface at every point inside the conductor
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parallel to the surface at every point and zero inside the conductor
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normal to the surface at every point and zero inside the conductor

The law, governing the force between electric charges is known as

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Ampere's law
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Ohm's law
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Faraday's law
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Coulomb's law

F_g and F_e represents gravitational and electrostatic force respectively between electrons situated at a distance 10 cm. The ratio of F_g/ F_e is of the order of

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10⁴²
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10
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1
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10^–43

Four charges are arranged at the corners of a square ABCD, as shown in the adjoining figure. The force on the charge kept at the centre O is

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Zero
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Along the diagonal AC
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Along the diagonal BD
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Perpendicular to side AB

In the absence of other conductors, the surface charge density

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Is proportional to the charge on the conductor and its surface area
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Inversely proportional to the charge and directly proportional to the surface area
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Directly proportional to the charge and inversely proportional to the surface area
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Inversely proportional to the charge and the surface area

Out of gravitational, electromagnetic, Vander Waals, electrostatic and nuclear forces; which two are able to provide an attractive force between two neutrons

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Electrostatic and gravitational
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Electrostatic and nuclear
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Gravitational and nuclear
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Some other forces like Vander Waals

Three charges 4q, Q, and q are in a straight line in the position of 0, l/2, and l respectively. The resultant force on q will be zero if Q =

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– q
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–2q
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$- \frac{q}{2}$
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4q

Two small spheres each having the charge +Q are suspended by insulating threads of length L from a hook. This arrangement is taken in space where there is no gravitational effect, then the angle between the two suspensions and the tension in each will be:

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$180^{o}, \frac{1}{4 π ε_{0}} \frac{Q^{2}}{{(2 L)}^{2}}$
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$90^{o}, \frac{1}{4 π ε_{0}} \frac{Q^{2}}{L^{2}}$
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$180^{o}, \frac{1}{4 π ε_{0}} \frac{Q^{2}}{2 L^{2}}$
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$180^{o}, \frac{1}{4 π ε_{0}} \frac{Q^{2}}{L^{2}}$

Two charges each of 1 coulomb are at a distance 1 km apart, the force between them is

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9 × 10³ Newton
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9 × 10^–3 Newton
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1.1 × 10^–4 Newton
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10⁴ Newton

Two charges +2 C and +6 C are repelling each other with a force of 12 N. If each charge is given –2 C of charge, then the value of the force will be:

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4 N (Attractive)
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4 N (Repulsive)
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8 N (Repulsive)
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Zero

The dielectric constant of pure water is 81. Its permittivity will be

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6.91 × 10^–10 MKS units
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8.86 × 10^–12 MKS units
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1.02 × 10¹³ MKS units
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Cannot be calculated

Force of attraction between two point charges Q and – Q separated by d meter is F_e. When these charges are given to two identical spheres of radius R = 0.3 d whose centres are d meter apart, the force of attraction between them is

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Greater than F_e
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Equal to F_e
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Less than F_e
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None of the above

One metallic sphere A is given a positive charge whereas another identical metallic sphere B of the exact same mass as of A is given an equal amount of negative charge. Then:

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mass of A and mass of B are the same.
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mass of A is more.
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mass of B is less.
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mass of B is more.

The force between two charges 0.06 m apart is 5 N. If each charge is moved towards the other by 0.01 m, then the force between them will become:

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7.20 N
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11.25 N
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22.50 N
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45.00 N

When 10¹⁹ electrons are removed from a neutral metal plate, the electric charge on it is?

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–1.6 C
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+1.6 C
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10⁺¹⁹ C
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10^–19 C

A solid conducting sphere of radius a has a net positive charge 2Q. A conducting spherical shell of inner radius b and outer radius c is concentric with the solid sphere and has a net charge –Q. The surface charge density on the inner and outer surfaces of the spherical shell will be?

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$- \frac{2 Q}{4 {πb}^{2}}, \frac{Q}{4 {πc}^{2}}$
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$- \frac{Q}{4 {πb}^{2}}, \frac{Q}{4 {πc}^{2}}$
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$0, \frac{Q}{4 {πc}^{2}}$
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None of the above

Three charges are placed at the vertices of an equilateral triangle of side ‘a’ as shown in the following figure. The force experienced by the charge placed at the vertex A in a direction normal to BC is

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$Q^{2} / (4 π ε_{0} a^{2})$
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$- Q^{2} / (4 π ε_{0} a^{2})$
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Zero
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$Q^{2} / (2 π ε_{0} a^{2})$

Two particles of equal mass m and charge q are placed at a distance of 16 cm. They do not experience any force. The value of $\frac{q}{m}$ is

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l
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$\sqrt{\frac{π ε_{0}}{G}}$
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$\sqrt{\frac{G}{4 π ε_{0}}}$
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$\sqrt{4 π ε_{0} G}$

An electron is moving around the nucleus of a hydrogen atom in a circular orbit of radius r. The Coulomb force $\vec{F}$ on electron is (Where $K = \frac{1}{4 π ε_{0}}$ )

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$- K \frac{e^{2}}{r^{3}} \hat{r}$
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$K \frac{e^{2}}{r^{3}} \vec{r}$
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$- K \frac{e^{2}}{r^{3}} \vec{r}$
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$K \frac{e^{2}}{r^{2}} \hat{r}$

Five balls numbered 1 to 5 are suspended using separate threads. Pairs (1, 2), (2, 4), and (4, 1) show electrostatic attraction, while pairs (2, 3) and (4, 5) show repulsion. Therefore ball 1 must be:

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positively charged.
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negatively charged.
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neutral.
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made of metal.

Equal charges q are placed at the four corners A, B, C, D of a square of length a. The magnitude of the force on the charge at B will be

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$\frac{3 q^{2}}{4 π ε_{0} a^{2}}$
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$\frac{4 q^{2}}{4 π ε_{0} a^{2}}$
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$(\frac{1 + 2 \sqrt{2}}{2}) \frac{q^{2}}{4 π ε_{0} a^{2}}$
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$(2 + \frac{1}{\sqrt{2}}) \frac{q^{2}}{4 π ε_{0} a^{2}}$

Two identical conductors of copper and aluminium are placed in an identical electric field. The magnitude of induced charge in the aluminum will be

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Zero
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Greater than in copper
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Equal to that in copper
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Less than in copper

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Practice Physics Quiz Questions and Answers

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Practice Physics Quiz Questions and Answers

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