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Measurements and Units (Multiple Choice)

Q1. Select the sets of quantities that both have the same unit

A
 Electrical resistivity and electrical resistance
B
 Work function Planck constant
C
 Pressure and the Young modulus.
D
 Acceleration and rate of change of momentum.

 

Q2. Which of the following is not a unit of power?

A
 N m s−1
B
kg m2 s −3
C
 J s−1
D
 kg m−1 s −1

Power is energy per second so C is a unit of power.

Energy is force x distance moved (Nm) so A is power also.

A newton is the unit of force - Force = mass x acceleration - so its unit is kg m s-2 - therefore the unit of energy (Nm) is kg m2 s-2 and power is kg m2 s-3 - so, B is correct

The answer is therefore D