B I think for 19 and D for 20
Answer:
63.8 V
Explanation:
We are given that





Potential difference,V=140 V
We know that

According to question

In series





Potential across 1.2 square cm=
Hence, the voltage across the 1.2 square cm wire=63.8 V
It takes 3 half-lives:
1. 1000 -> 500
2. 500 -> 250
3. 250 ->125
I'm not sure about the Virginia thing so good luck!
And congratulations on being my first answer-person!!
Answer:wdym insulation if u mean like covering than the ppls heads
Explanation:
Thomson experiment he calculated the charge to mass ratio just be passing the fundamental charge through a tube
He calculated the charge to mass ratio just by finding the deflection of charge while it is passing through the constant electric field
so here we will use the deflection as following
let say it passes the field of length "L"
so here we have

now in the same time if it deflect by some distance


now by solving this equation we can find e/m ratio
so here correct answer will be
the electron's charge-to-mass ratio