A charge ${q_1}$ exerts some force on a second charge ${q_2}$. If third charge ${q_3}$ is brought near, the force of ${q_1}$ exerted on ${q_2}$
Decreases
Increases
Remains unchanged
Increases if ${q_3}$ is of the same sign as ${q_1}$ and decreases if ${q_3}$ is of opposite sign
The plates $S$ and $T$ of an uncharged parallel plate capacitor are connected across a battery. The battery is then disconnected and the charged plates are now connected in a system as shown in the figure. The system shown is in equilibrium. All the strings are insulating and massless. The magnitude of charge on one of the capacitor plates is: [Area of plates = $A$]
Two protons $A$ and $B$ are placed in space between plates of a parallel plate capacitor charged upto $V$ volts (See fig.) Forces on protons are ${F_A}$ and ${F_B}$, then
A negatively charged particle $p$ is placed, initially at rest, in $a$ constant, uniform gravitational field and $a$ constant, uniform electric field as shown in the diagram. What qualitatively, is the shape of the trajectory of the electron?
A paisa coin is made up of $\mathrm{Al - Mg}$ alloy and weighs $0.75\, g$ It is electrically neutral and contains equal amounts of positive and negative charge of magnitude $34.8$ $\mathrm{kC}$. Suppose that these equal charges were concentrated in two point charges separated by :
$(i)$ $1$ $\mathrm{cm}$ $(\sim \frac{1}{2} \times $ diagonal of the one paisa coin $)$
$(ii)$ $100\,\mathrm{m}$ $(\sim $ length of a long building $)$
$(iii)$ $10^6$ $\mathrm{m}$ (radius of the earth).
Find the force on each such point charge in each of the three cases. What do you conclude from these results ?
Write value of Coulombian constant $k$ in $SI$ unit.