Step-by-step explanation:
It is given that,
Mass of the object, m = 0.8 g = 0.0008 kg
Electric field, E = 534 N/C
Distance, s = 12 m
Time, t = 1.2 s
We need to find the acceleration of the object. It can be solved as :
m a = q E.......(1)
m = mass of electron
a = acceleration
q = charge on electron
"a" can be calculated using second equation of motion as :
![s=ut+(1)/(2)at^2](https://img.qammunity.org/2020/formulas/physics/middle-school/z381q7xga85qdtp5e9fiz6dr16bacc3cy2.png)
![s=0+(1)/(2)at^2](https://img.qammunity.org/2020/formulas/physics/college/wm2ln7srxw4i8j2on5i6dvaaj75u4m9zp0.png)
![a=(2s)/(t^2)](https://img.qammunity.org/2020/formulas/physics/college/ujmuifzx4xpt1spwcjjrju068xgnk0jvqz.png)
![a=(2* 12\ m)/((1.2\ s)^2)](https://img.qammunity.org/2020/formulas/physics/college/m2ir5p28ax0reu871s2fcbgwolgh5avgfu.png)
a = 16.67 m/s²
Now put the value of a in equation (1) as :
![q=(ma)/(E)](https://img.qammunity.org/2020/formulas/physics/college/pmi3yhi6hbusnj04z6lvveyatn2pyy3dvw.png)
![q=(0.0008\ kg* 16.67\ m/s^2)/(534\ N/C)](https://img.qammunity.org/2020/formulas/physics/college/oql3b935h1iwz5k0f46prtlk7y2ju7ye8a.png)
q = 0.0000249 C
or
![q=2.49* 10^(-5)\ C](https://img.qammunity.org/2020/formulas/physics/college/gokajwkj07a6xyhrno4gborqo1ggme28r7.png)
Hence, this is the required solution.