Is there a point between a 10 nc charge and a 20 nc charge at which the electric field is zero?

Let 10 nC and 20 nC charge is placed at "d" distance

now let say we will have a point at distance "x" from 10 nC at which electric field will be zero

now we will have

now plug in all data

square root both sides

so yes there will exist a point between 10 nC and 20 nC charge at which electric field will be zero

f=ma newton

f=100x2.5=250n

when a device is used in a circuit in which the voltage is 81 v, the current flowing through the device is 3 a. what is the resistance of the device?

a. 27 ω

b. 40.5 a

c. 243 ω

d. 243 a

the correct answer is a. 27