The diagram shows a spherical surface which separates two media of refractive indices, ${\mu }_1$ and ${\mu }_2$, respectively. Now, a point object is placed on the principal axis as shown in the figure. Then

• A

  Real image will form if ${\mu }_1>{\mu }_2$ and for all values of $u$
• B

  Real image for some values of $u$ if ${\mu }_1>{\mu }_2$
• Correct answer
  C

  Virtual image will form if ${\mu }_1>{\mu }_2$
• D

  Virtual image will form if ${\mu }_1<{\mu }_2$

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