Physics, 25.11.2019 07:31 shamiahG

True or false?

1. lenz's law states that the induced current and induced emf in a conductor are in such a direction as to enhance the magnetic flux change that produced them. t/f2. the magnitude flux through a surface depends on the magnitudes of magnetic field and surface area only. t/f3. like a sound wave, propagation of em waves requires air as a medium. t/f

Answers: 1

Show answers

Answers

Answer from: tangia

1. False

Explanation: it's exactly the opposite. In fact, Lenz's law states that the induced current and the induced emf in a conductor are generated in such a direction that opposes to the change in magnetic flux through the coil. This is summarized by the negative sign in the Faraday's Newmann Lenz law:

$\epsilon= -\frac{d\Phi }{dt}$

where $\epsilon$ is the emf induced and $\frac{d\Phi}{dt}$ is the rate of change of magnetic flux through the coil.

Lenz's law is a consequence of the law of conservation of energy. In fact, we have:

- If the magnetic flux through a coil is increasing, then the induced current has a direction such that the magnetic field generated by the coil is opposite to the direction of the external magnetic field, in order to decrease the total flux

- If the magnetic flux through a coil is decreasing, then the induced current has a direction such that the magnetic field generated by the coil is in the same direction as the external field, in order to increase the total flux

2. False

Explanation: the magnetic flux through a surface is given by

$\Phi = BA cos \theta$

where

B is the magnitude of the magnetic field

A is the surface area

$\theta$ is the angle between the direction of B and the normal vector to the surface

As we see, the magnetic flux depends not only on B and A, but also on the orientation of the coil with respect to the magnetic field.

3. False

Explanation:

- Sound waves are mechanical waves: mechanical waves are waves consisting of oscillations of the particles in a medium. Due to their nature, therefore, mechanical waves can propagate only in the presence of a medium

- Electromagnetic waves are NOT mechanical waves: they consist of oscillations of electric and magnetic fields, in a direction perpendicular to the direction of propagation of the wave. Since em waves are not mechanical waves, they do NOT need a medium to propagate, since they can also travel through a vacuum; therefore the original statement is false.

Answer from: Quest

u=13

v=30

s/t=u+1\2at

=13+431/2

=13+265.5

=278.5

Answer from: Quest

i think the answer is a, hope this is right, that would be my best guess.

When describing image formation for flat, shiny surfaces, what is an important rule to remember abou

Another question on Physics

Physics, 22.06.2019 02:40

If the wheels lock when braking suddenly the vehicle: a: loses traction b: lose steering wheel ability c: gain speed slightly d: gain steering ability

Answers: 1

Answer

Physics, 22.06.2019 09:30

Which of these is not a possible type of energy transformation? a. electrical energy into light energy b. sound energy into nuclear energy c. potential energy into kinetic energy d. kinetic energy into mechanical energy

Answers: 1

Answer

Physics, 22.06.2019 16:30

In a heat engine if 1000 j of heat enters the system and the piston does 500j of work, what is the final internal energy of the system if the inital energy was 2000 j1.write the equation2.list out your known variables 3. plug the numbers into the equations4.solve 5.write your solution statement that includes initial energy and final energy added.

Answers: 3

Answer

Physics, 22.06.2019 18:10

Which of the following statement is false

Answers: 2

Answer

You know the right answer?

True or false?

1. lenz's law states that the induced current and induced emf in a condu...

Questions