Answer:
(a) Electric field is much larger
(b) [tex]3.924\times10^{-4}C[/tex]
Explanation:
An electron being negatively charged will experience a force in a direction opposite to that of the electric field, that is, the force will be upwards (electric field being downwards).
The force experienced by the electron due to the electric filed is given by:
[tex]F_E=e\times E=(1.6\times 10^{-19}C)\times(150N/C)=2.4\times10^{-17}N[/tex]
Force due to gravity (downward direction):
[tex]F_g=m_eg=(9.1\times10^{-31}kg)\times(9.81m/s^2)=8.93\times10^{-30}N[/tex]
Hence, the electric field is much larger.
It is given that a penny has mass [tex]m=6g=0.006kg[/tex]
Gravitational force = mg = 0.05886 N
To balance that we have to put, say, q amount of negative charge on the penny. Therefore,
[tex]qE=mg[/tex]
or, [tex]q=\frac{mg}{E}=\frac{0.05886}{150}C=3.924\times10^{-4}C[/tex]
