Answer:
A physical change
Explanation:
You are wiping chalk particles from the board to the eraser which is just changing the location of the chalk particles, a physical change.
you're not changing the chalk into a new substance or causing a chemical reaction, which would be a chemical change.
Answer:
a) 6.9*10^14 Hz
b) 9*10^-12 T
Explanation:
Given that
The wavelength of the wave, λ = 435 nm
Amplitude of the electric field, E(max) = 2.7*10^-3 V/m
a)
The frequency of the wave can be found by using the formula
c = fλ, where c = speed of light
f = c/λ
f = 3*10^8 / 435*10^-9
f = 6.90*10^14 Hz
b)
E(max) = B(max) * c, magnetic field amplitude, B(max) =
B(max) = E(max)/c
B(max) = 2.7*10^-3 / 3*10^8
B(max) = 9*10^-12 T
c)
1T = 1 (V.s/m^2)
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Answer:
Option (b) is correct.
Explanation:
The motion under the influence of gravity is called projectile motion.
The acceleration due to gravity is constant through out the motion and it is always acting downwards.
When an athlete jumps and follow the projectile path, it always have the same horizontal velocity as there is no acceleration in the horizontal direction.
Also he has the vertical acceleration constant which is equal to the acceleration due to gravity and acts towards the center of earth.
Option (b) is correct.
Answer:
<h3>The answer is 36 J</h3>
Explanation:
The work done by an object can be found by using the formula
workdone = force × distance
From the question we have
workdone = 3 × 12
We have the final answer as
<h3>36 J</h3>
Hope this helps you
