02. COULOMB'S LAW
Electric Charges and Fields

272147 Force between two identical charges placed at a distance of $r$ in vacuum is $F$. Now a slab of dielectric of dielectric contrant 4 is inserted between these two charges. If the thickness of the slab is $r/2$, then the force between the charges will become

1 $F$
2 $\frac{3}{5}~F$
3 $\frac{4}{9}~F$
4 $\frac{F}{2}$
Electric Charges and Fields

272148 Two particle 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

1 1
2 $\sqrt{\frac{\pi {{\varepsilon }_{0}}}{G}}$
3 $\sqrt{\frac{G}{4\pi {{\varepsilon }_{0}}}}$
4 $\sqrt{4\pi {{\varepsilon }_{0}}G}$
Electric Charges and Fields

272149 Three identical charged balls each of charge $2C$ are suspended from a common point $P$ by silk threads of $2m$ each (as shown in figure). They form an equilateral triangle of side $1~m$.
The ratio of net force on a charged ball to the force between any two charged balls will be :

1 $1:1$
2 $1:4$
3 $\sqrt{3}:2$
4 $\sqrt{3}:1$
Electric Charges and Fields

272150 Sixty four conducting drops ${{~}^{{{B}_{1}}}}$ each of radius 0.02m and each carrying a charge of $5\mu C$ are combined to form a bigger drop. Ratio of surface density of bigger drop to the smaller drop will be:

1 $1:4$
2 $4:1$
3 $1:8$
4 $8:1$
Electric Charges and Fields

272147 Force between two identical charges placed at a distance of $r$ in vacuum is $F$. Now a slab of dielectric of dielectric contrant 4 is inserted between these two charges. If the thickness of the slab is $r/2$, then the force between the charges will become

1 $F$
2 $\frac{3}{5}~F$
3 $\frac{4}{9}~F$
4 $\frac{F}{2}$
Electric Charges and Fields

272148 Two particle 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

1 1
2 $\sqrt{\frac{\pi {{\varepsilon }_{0}}}{G}}$
3 $\sqrt{\frac{G}{4\pi {{\varepsilon }_{0}}}}$
4 $\sqrt{4\pi {{\varepsilon }_{0}}G}$
Electric Charges and Fields

272149 Three identical charged balls each of charge $2C$ are suspended from a common point $P$ by silk threads of $2m$ each (as shown in figure). They form an equilateral triangle of side $1~m$.
The ratio of net force on a charged ball to the force between any two charged balls will be :

1 $1:1$
2 $1:4$
3 $\sqrt{3}:2$
4 $\sqrt{3}:1$
Electric Charges and Fields

272150 Sixty four conducting drops ${{~}^{{{B}_{1}}}}$ each of radius 0.02m and each carrying a charge of $5\mu C$ are combined to form a bigger drop. Ratio of surface density of bigger drop to the smaller drop will be:

1 $1:4$
2 $4:1$
3 $1:8$
4 $8:1$
Electric Charges and Fields

272147 Force between two identical charges placed at a distance of $r$ in vacuum is $F$. Now a slab of dielectric of dielectric contrant 4 is inserted between these two charges. If the thickness of the slab is $r/2$, then the force between the charges will become

1 $F$
2 $\frac{3}{5}~F$
3 $\frac{4}{9}~F$
4 $\frac{F}{2}$
Electric Charges and Fields

272148 Two particle 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

1 1
2 $\sqrt{\frac{\pi {{\varepsilon }_{0}}}{G}}$
3 $\sqrt{\frac{G}{4\pi {{\varepsilon }_{0}}}}$
4 $\sqrt{4\pi {{\varepsilon }_{0}}G}$
Electric Charges and Fields

272149 Three identical charged balls each of charge $2C$ are suspended from a common point $P$ by silk threads of $2m$ each (as shown in figure). They form an equilateral triangle of side $1~m$.
The ratio of net force on a charged ball to the force between any two charged balls will be :

1 $1:1$
2 $1:4$
3 $\sqrt{3}:2$
4 $\sqrt{3}:1$
Electric Charges and Fields

272150 Sixty four conducting drops ${{~}^{{{B}_{1}}}}$ each of radius 0.02m and each carrying a charge of $5\mu C$ are combined to form a bigger drop. Ratio of surface density of bigger drop to the smaller drop will be:

1 $1:4$
2 $4:1$
3 $1:8$
4 $8:1$
Electric Charges and Fields

272147 Force between two identical charges placed at a distance of $r$ in vacuum is $F$. Now a slab of dielectric of dielectric contrant 4 is inserted between these two charges. If the thickness of the slab is $r/2$, then the force between the charges will become

1 $F$
2 $\frac{3}{5}~F$
3 $\frac{4}{9}~F$
4 $\frac{F}{2}$
Electric Charges and Fields

272148 Two particle 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

1 1
2 $\sqrt{\frac{\pi {{\varepsilon }_{0}}}{G}}$
3 $\sqrt{\frac{G}{4\pi {{\varepsilon }_{0}}}}$
4 $\sqrt{4\pi {{\varepsilon }_{0}}G}$
Electric Charges and Fields

272149 Three identical charged balls each of charge $2C$ are suspended from a common point $P$ by silk threads of $2m$ each (as shown in figure). They form an equilateral triangle of side $1~m$.
The ratio of net force on a charged ball to the force between any two charged balls will be :

1 $1:1$
2 $1:4$
3 $\sqrt{3}:2$
4 $\sqrt{3}:1$
Electric Charges and Fields

272150 Sixty four conducting drops ${{~}^{{{B}_{1}}}}$ each of radius 0.02m and each carrying a charge of $5\mu C$ are combined to form a bigger drop. Ratio of surface density of bigger drop to the smaller drop will be:

1 $1:4$
2 $4:1$
3 $1:8$
4 $8:1$