Answer:
ΔE = 1.36 × 10⁻¹⁹ J
Solution:
Using Bohr Energy Equation,
ΔE = - R (1/nₐ² - 1/nₓ²)
Where;
R = Rydberg's constant = 2.18 × 10⁻¹⁸ J
nₐ = Infinity = ∞
nₓ = 4
Putting Values in equation 1,
ΔE = - 2.18 × 10⁻¹⁸ J × ( 1/∞² - 1/4²)
ΔE = - 2.18 × 10⁻¹⁸ J × ( 0 - 0.0625)
ΔE = 1.36 × 10⁻¹⁹ J