Answer:
(a)
(b) 
Explanation:
Part (a)
The total length of copper cord L=86.3 m
The cross sectional area A=1.71×10⁻⁶m²
The resistivity of copper p=1.72×10⁻⁸Ω
Thus the resistance of extension cord is

Part (b)
The resistance of trimmer Rt=17.9 ohms
When voltage of 120V is applied then the current I is passing through series circuit is

Thus the voltage across the trimmer is:

Answer:
Explanation:
The standard equation of the sinusoidal wave in one dimension is given by

Here, A be the amplitude of the wave
λ be the wavelength of the wave
v be the velocity of the wave
Φ be the phase angle
x be the position of the wave
t be the time
this wave is travelling along positive direction of X axis
The frequency of wave is f which relates with velocity and wavelength as given below
v = f x λ
The relation between the time period and the frequency is
f = 1 / T.
No. I do not agree with Stefan. Quite the contrary. I disagree
with his description of "<span>angle of incidence" as the angle between
the surface of the mirror and the incoming ray.
The correct description of "angle of incidence" is </span><span>the angle between
the NORMAL TO the surface of the mirror and the incoming ray.
Thus, the true angle of incidence is the complement of the angle that
Stefan calculates or measures.</span>
Answer:
Atoms are composed of electrons (charge -1), protons (charge +1), and neutrons (no charge). So in a neutral atom the correct answer is "D".