Answer:
Explanation:
Given that,
Number of turns is 119
N = 119
The radius of the coils is 2.47 cm
R = 2.47 cm = 0.0247m
Then, the area of the circular coil is given as
A = πr²
A = π × 0.0247²
A = 1.917 × 10^-3 m²
Time interval
t = 0.167s
The magnetic field strength increases from B1 = 57.9mT to B2 = 96.9 mT
Then,
∆B = B2 - B1 = 96.9 — 57.9 = 39 mT
∆B = 39 × 10^-3 T
We want find the average emf
EMF induced in a coil is given as
ε = -N dΦ / dt
Then, magnetic flux (Φ) is given as
Φ = BA
Then,
ε = -N dΦ / dt
ε = -N d(BA) / dt
Since the area is constant, so we have
ε = -N•A dB / dt
ε = -N •A • ∆B / ∆t
So, inserting the parameters above
ε = - 199 × 1.917 × 10^-3 × 39 × 10^-3 / 0.167
ε = 0.0891 V
To mV
ε = 89.1 × 10^-3 V
ε = -89.1 mV
Then, the magnitude of EMF induced in the coil is 89.1 mV
I strongly believe that it is C just because this could not actually occur so the only thing that could happen is that she didn't talk as quietly as she thought she did.
Hope I helped!!!!
The answer should be B.
Hope it helped you.
Answer:
a)
Explanation:
- A block sliding down an inclined plane, is subject to two external forces along the slide.
- One is the component of gravity (the weight) parallel to the incline.
- If the inclined plane makes an angle θ with the horizontal, this component (projection of the downward gravity along the incline, can be written as follows:
(taking as positive the direction of the movement of the block)
- The other force, is the friction force, that adopts any value needed to meet the Newton's 2nd Law.
- When θ is so large, than the block moves downward along the incline, the friction force can be expressed as follows:
- The normal force, adopts the value needed to prevent any vertical movement through the surface of the incline:
- In equilibrium, both forces, as defined in (1), (2) and (3) must be equal in magnitude, as follows:
- As the block is moving, if the net force is 0, according to Newton's 2nd Law, the block must be moving at constant speed.
- In this condition, the friction coefficient is the kinetic one (μk), which can be calculated as follows:
The correct option is D.
Destructive interference is said to occur when two waves superpose in such a way that they cancel each other out. The two waves are usually of equal frequency and opposite phase, the negative displacement of one wave collides with the positive displacement of the other wave, thus cancelling each other out.<span />