Here's a tip: The unit of frequency ... Hertz or Hz ... means "per second". "Five times PER SECOND" is a frequency of 5 Hz.
Is there supposed to be a picture? Next time try putting a picture
Answer:
C) 16.3 ml
Explanation:
Density is equal to the ratio between the mass of an object and its volume:

where
m is the mass
V is the volume
In our problem, we know:
- density of aluminium: 
- mass of the aluminium foil: 
So we can re-arrange the equation above and use these data to find the volume of the piece of aluminium foil:

Answer:
2.49 * 10^(-4) m
Explanation:
Parameters given:
Frequency, f = 4.257 MHz = 4.257 * 10^6 Hz
Speed of sound in the body, v = 1.06 km/ = 1060 m/s
The speed of a wave is given as the product of its wavelength and frequency:
v = λf
Where λ = wavelength
This implies that:
λ = v/f
λ = (1060) / (4.257 * 10^6)
λ = 2.49 * 10^(-4) m
The wavelength of the sound in the body is 2.49 * 10^(-4) m.
Explanation:
It is given that,
Diameter of the circular loop, d = 1.5 cm
Radius of the circular loop, r = 0.0075 m
Magnetic field, 
(A) We need to find the current in the loop. The magnetic field in a circular loop is given by :



I = 32.22 A
(b) The magnetic field on a current carrying wire is given by :



r = 0.00238 m

Hence, this is the required solution.