Select the correct alternative
The charge gained by the uncharged body from a charged body due to conduction is equal to half of the total charge initially present
The magnitude of charge increases with the increase in velocity of charge
Charge can exist without matter although matter can not exist without charge
Between two non-magnetic substances repulsion is the true test of electrification (electrification means body has net charge)
The ratio of gravitational force and electrostatic repulsive force between two electrons is approximately (gravitational constant $=6.7 \times 10^{-11} \,Nm ^2 / kg ^2$, mass of an electron $=9.1 \times 10^{-31} \,kg$, charge on an electron $=1.6 \times 10^{-19} C$ )
A point charge $q_1$ exerts force $F$ upon another point charge $q_2$. If a third charge $q_3$ be placed near the charge $q_2$, then the force that charge $q_1$ exerts on the charge $q_2$ will be
There are two charges $+1$ microcoulombs and $+5$ microcoulombs. The ratio of the forces acting on them will be
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 | $4.\quad$ $-y$ |
Two free point charges $+q$ and $+4q$ are a distance $R$ apart. $A$ third charge is so placed that the entire system is in equilibrium. Then the third charge is :-