The intensity of a wave can be defined as the energy per unit area per unit time. What is the unit of intensity expressed in fundamental SI units?

A.  kg m⁻²s⁻¹

B.  kg m²s⁻³

C.  kg s⁻²

D.  kg s⁻³

A student is verifying the equation

$$x=\frac{2\lambda Y}{z}$$

The percentage uncertainties are:

What is the percentage uncertainty in x?

A. 5 %

B. 15 %

C. 25 %

D. 30 %

Four particles, two of charge +Q and two of charge −Q, are positioned on the $x$-axis as shown. A particle P with a positive charge is placed on the $y$-axis. What is the direction of the net electrostatic force on this particle?

The uncertainty in reading a laboratory thermometer is 0.5 °C. The temperature of a liquid falls from 20 °C to 10 °C as measured by the thermometer. What is the percentage uncertainty in the change in temperature?

A.  2.5 %

B.  5 %

C.  7.5 %

D.  10 %

What is a correct value for the charge on an electron?

A. 1.60 x 10^–12 μC

B. 1.60 x 10^–15 mC

C. 1.60 x 10^–22 kC

D. 1.60 x 10^–24 MC

Which is a correct unit for gravitational potential?

A. m²s⁻²

B. J kg

C. m s⁻²

D. N m⁻¹kg⁻¹

A proton has momentum 10^-20 N s and the uncertainty in the position of the proton is 10^-10 m. What is the minimum fractional uncertainty in the momentum of this proton?

A. 5 × 10^-25

B. 5 × 10^-15

C. 5 × 10^-5

D. 2 × 10⁴