Question

If an electron starts from rest from a point at which potential is 50 volt to another point at which potential is 70 volt, then its kinetic energy in the final state will be

• A. $3.2\times {10}^{-10}J$
  
• B. $3.2\times {10}^{-18}J$
• C. $1J$
• D. $1dyne$

Answer 1

The correct option is B $3.2\times {10}^{-18}J$

$K.E.=q_0(V_A-V_B)=1.6\times {10}^{-19}(70-50)=3.2\times {10}^{-18}J$