Snell's Law determines the angle of refraction Steps:

• Use Snell's law: n_air sin i = n_glass sin r, where n_air = 1, i = 45°, n_glass = 1.5.
• Calculate sin i = sin 45° = √2 / 2 ≈ 0.707.
• Solve for sin r = sin i / n_glass ≈ 0.707 / 1.5 ≈ 0.471.
• Find r = arcsin(0.471) ≈ 28°.

Why none of the options are exactly correct:

• The calculated angle of refraction is approximately 28°, but no option matches; options may contain an error.
• A (23°): Underestimates the angle; sin 23° ≈ 0.391, leading to i ≈ 36° for n=1.5.
• B (25°): Closest but still low; sin 25° ≈ 0.423, leading to i ≈ 39°.
• C (45°): Equals i, ignoring refraction; would require n=1.
• D (81°): Too large; sin 81° ≈ 0.988, exceeding sin i / n limit.

Final answer: Approximately 28° (none of the options)