Consider the following three statements:
1 A mass of 4.0 kg requires a resultant force of 5.0 N to act on it in order to
accelerate it at 1.25 m / s 2
.
2 A wave of frequency 4.0 Hz travelling at a speed of 5.0 m / s has a wavelength of
1.25 m.
3 A voltage of 4.0 V applied across a 5.0 Ω resistor causes a current of 1.25 A to
flow.
Which statement(s) is / are true?

Answer:

27) D

1 – Force = mass x acceleration (F = ma)
Force required = 4kg x 1.25 = 5N.
Hence statement 1 is correct.

2 – Speed = frequency x wavelength (c = ƒ x λ)
ƒ = c ÷ λ
4 = 5 ÷ 1.25
Hence statement 2 is correct.

3 – Voltage = Current x Resistance (V = IR)
However, 4 ≠ 5 x 1.25
5 x 1.25 = 6.25
So statement 3 is wrong.

Only statements 1 and 2 are correct. So the answer is D.