1. Use Einstein’s photoelectric equation

   $K_{\max} = h\nu - \phi$

   where:

   • $h\nu = 2.48\,\text{eV}$ is the energy of incident photon,
   • $\phi$ is the work function,
   • $K_{\max}$ is the maximum kinetic energy of emitted electrons.

2. Relate stopping potential to maximum kinetic energy

   $K_{\max} = eV_0$

   Since the stopping potential is $V_0 = 0.5\,\text{V}$, the maximum kinetic energy is

   $K_{\max} = 0.5\,\text{eV}$

   because $1\,\text{eV}$ corresponds to an electron accelerated through $1\,\text{V}$.

3. Find the work function

   From

   $\phi = h\nu - K_{\max}$

   substitute the values:

   $\phi = 2.48 - 0.5 = 1.98\,\text{eV}$

4. Match with the options

   • A: $1.98\,\text{eV}$ ✅
   • B: $1.68\,\text{eV}$ ❌
   • C: $2.48\,\text{eV}$ ❌
   • D: $0.5\,\text{eV}$ ❌

Therefore, the work function of the material is:

$\boxed{1.98\,\text{eV}}$