Which of the following is the correct lens formula?

• Correct answer
  A

  $\frac{1}{\mathrm{v}}-\frac{1}{\mathrm{u}}=\frac{1}{\mathrm{f}}$
• B

  $\frac{1}{\mathrm{v}}+\frac{1}{\mathrm{u}}=\frac{1}{\mathrm{f}}$
• C

  $v-u=f$
• D

  $\mathrm{v}+\mathrm{u}=\mathrm{f}$

Hence, the correct answer is option: 'A'.