Electric field from proton's acceleration Steps:

• The force due to the electric field is F = qE, where q = 1.6 × 10^{-19} C is the proton charge.
• This force causes acceleration, so F = ma, where m = 1.6 × 10^{-27} kg is the proton mass (approximate) and a = 2.0 × 10^9 m/s².
• Set equal: qE = ma.
• Solve: E = ma / q = (1.6 × 10^{-27} × 2.0 × 10^9) / 1.6 × 10^{-19} = 20 V/m. Why D is correct:
• It matches E = ma/q using standard proton properties and the given acceleration. Why the others are wrong:
• A underestimates by factor of ~18 (ignores full mass or acceleration scale).
• B underestimates by factor of ~4 (partial miscalculation of ma).
• C underestimates by factor of 2 (halves the force term). Final answer: D