An electron falls through a distance of \(1.5\) cm in a uniform electric field of magnitude \(2\times10^4\) N/C [figure (a)]. The direction of the field is reversed keeping its magnitude unchanged and a proton falls through the same distance [figure (b)]. If \(t_e\) and \(t_p\) are the time of fall for electron and proton respectively, then:

   
1. \(t_e=t_p\)
2. \(t_e>t_p\)
3. \(t_e<t_p\)
4. none of these$\mathrm{}$

Two-point charges $q_1$ and $q_2$, of magnitude $+{10}^{-8} C$  and $-{10}^{-8} C$, respectively, are placed 0.1 m apart. The electric field at point  A (as shown in the figure) is: 

$1. 3.6\times {10}^4 {\mathrm{NC}}^{-1}$
$2. 7.2\times {10}^4 {\mathrm{NC}}^{-1}$
$3. 9\times {10}^3 {\mathrm{NC}}^{-1}$
$4. 3.2\times {10}^4 {\mathrm{NC}}^{-1}$