20N•m or 20J. Work is equal to force•distance, and 5N•4m is 20N•m, or J
Answer:
refractive index of the unknown material is 1.33.
Explanation:
μ₁ = 1.21
incidence angle (i) = 41.9°
refraction angle (r) = 37.3°
Let us assume μ be the refractive index of the unknown material
according to snell's law of refraction.
μ₁ sin i = μ₂ sin r
1.21 × sin 41.9° = μ × sin 37.3°
μ = 1.33
hence the refractive index of the unknown material comes out top be 1.33
<span>The correct answer is C) a motor.
In particular, we are talking about an AC motor, which produces an alternating current. In an AC motor, a coil is immersed in a rotating magnetic field. Due to the motion of the magnetic field,the angle between the direction of the field and the surface enclosed by the coil changes. As a result, the magnetic flux through the coil changes over time (the magnetic flux is given by:
</span>

<span>
where B is the intensity of the magnetic field, A is the area enclosed by the coil and </span>

<span> is the angle between the direction of B and the perpendicular to the plane of the coil). For Faraday-Newmann-Lenz law, this change in flux induces an electromotive force (emf) into the coil, according to:
</span>

<span>
where the numerator is the variation of magnetic flux and dt is the time interval. This emf in the coil produced an electrical current in the circuit.</span>
Answer:
The work done on the box is 80 J.
Explanation:
Given that,
Weight of box = 40 N
Distance = 2 meter
We need to calculate the work done
Using formula of work done


Where, x = distance
mg = weight
Put the value into the formula



Hence, The work done on the box is 80 J.
Answer:
44.1 m
Explanation:
<u>Given:</u>
= speed of sound in air = 343 m/s
= speed of sound in the rod = 
= times interval between the hearing the sound twice = 0.12 s
<u>Assumptions:</u>
= length of the rod
= time taken by the sound to travel through the rod
= time taken by the sound to travel to through air to the same point = 
We know that the distance traveled by the sound in a particular medium is equal to the product of the speed of sound in that medium and the time taken.
For traveling sound through the rod, we have
..........eqn(1)
For traveling sound through the air to the women ear for traveling the same distance, we have

Hence, the length of the rod is 44.1 m.