Step 1: Conservation of momentum
\[ m_Y v_Y = m_Z v_Z \]
\[ \frac{v_Y}{v_Z} = \frac{m_Z}{m_Y} \]
Step 2: Kinetic energy relation
\[ K = \frac{1}{2} m v^2 \]
\[ \frac{K_Y}{K_Z} = \frac{m_Y v_Y^2}{m_Z v_Z^2} \]
Step 3: Substitute velocity ratio
\[ \frac{K_Y}{K_Z} = \frac{m_Y}{m_Z} \left(\frac{m_Z}{m_Y}\right)^2 \]
\[ = \frac{m_Z}{m_Y} \]
Step 4: Substitute values
\[ \frac{K_Y}{K_Z} = \frac{140}{100} = \frac{7}{5} \]
Final Answer: \( 7:5 \)
If Planck's constant is \( 6.63 \times 10^{-34} \) Js, then the slope of a graph drawn between cut-off voltage and frequency of incident light in a photoelectric experiment is: