Four point charges, each of $+ q$, are rigidly fixed at the four corners of a square planar soap film of side ' $a$ ' The surface tension of the soap film is $\gamma$. The system of charges and planar film are in equilibrium, and $a=k\left[\frac{q^2}{\gamma}\right]^{1 / N}$, where ' $k$ ' is a constant. Then $N$ is
Four point charges, each of $+ q$, are rigidly fixed at the four corners of a square planar soap film of side ' $a$ ' The surface tension of the soap film is $\gamma$. The system of charges and planar film are in equilibrium, and $a=k\left[\frac{q^2}{\gamma}\right]^{1 / N}$, where ' $k$ ' is a constant. Then $N$ is
- [IIT 2011]
- A
$3$
- B
$6$
- C
$4$
- D
$5$
Similar Questions
Four charge $Q _1, Q _2, Q _3$, and $Q _4$, of same magnitude are fixed along the $x$ axis at $x =-2 a - a ,+ a$ and $+2 a$, respectively. A positive charge $q$ is placed on the positive $y$ axis at a distance $b > 0$. Four options of the signs of these charges are given in List-$I$ . The direction of the forces on the charge q is given in List-$II$ Match List-$1$ with List-$II$ and select the correct answer using the code given below the lists.$Image$
List-$I$
List-$II$
$P.$ $\quad Q _1, Q _2, Q _3, Q _4$, all positive
$1.\quad$ $+ x$
$Q.$ $\quad Q_1, Q_2$ positive $Q_3, Q_4$ negative
$2.\quad$ $-x$
$R.$ $\quad Q_1, Q_4$ positive $Q_2, Q_3$ negative
$3.\quad$ $+ y$
$S.$ $\quad Q_1, Q_3$ positive $Q_2, Q_4$ negative
$4.\quad$ $-y$
Four charge $Q _1, Q _2, Q _3$, and $Q _4$, of same magnitude are fixed along the $x$ axis at $x =-2 a - a ,+ a$ and $+2 a$, respectively. A positive charge $q$ is placed on the positive $y$ axis at a distance $b > 0$. Four options of the signs of these charges are given in List-$I$ . The direction of the forces on the charge q is given in List-$II$ Match List-$1$ with List-$II$ and select the correct answer using the code given below the lists.$Image$
| List-$I$ | List-$II$ |
| $P.$ $\quad Q _1, Q _2, Q _3, Q _4$, all positive | $1.\quad$ $+ x$ |
| $Q.$ $\quad Q_1, Q_2$ positive $Q_3, Q_4$ negative | $2.\quad$ $-x$ |
| $R.$ $\quad Q_1, Q_4$ positive $Q_2, Q_3$ negative | $3.\quad$ $+ y$ |
| $S.$ $\quad Q_1, Q_3$ positive $Q_2, Q_4$ negative | $4.\quad$ $-y$ |
- [IIT 2014]
Three identical charged balls each of charge $2 \,C$ are suspended from a common point $P$ by silk threads of $2 \,m$ 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 ...........
Three identical charged balls each of charge $2 \,C$ are suspended from a common point $P$ by silk threads of $2 \,m$ 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 ...........
- [JEE MAIN 2022]
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According to Coulomb's Law, which is correct relation for the following diagram?
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Two charges each equal to $2\,\mu C$ are $0.5\,m$ apart. If both of them exist inside vacuum, then the force between them is.......$N$
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