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3 years ago

In the photoelectric effect, the greater the frequency of the illuminating light, the greater the:_______

Physics

1 answer:

TEA [102]3 years ago

8 0

Answer:

B. Maximum velocity of ejected electrons.

Explanation:

The ejection of electrons form a metal surface when the metal surface is exposed to a monochromatic electromagnetic wave of sufficiently short wavelength or higher frequency (or equivalently, above a threshold frequency), which leads to the enough energy of the wave to incident and get absorbed to the exposed surface emits electrons. This phenomenon is known as the photoelectric effect or photo-emission.

The minimum amount of energy required by a metal surface to eject an electron from its surface is called work function of metal surface.

The electrons thus emitted are called photo-electrons.

The current produced as a result is called photo electricity.

Energy of photon is given by:

$E=h.\nu$

where:

h = Planck's constant

$\nu=$ frequency of the incident radiation.

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A kangaroo jumps straight up to a vertical height of 1.66 m. How long was it in the air before returning to Earth? Express your

Nataly [62]

Answer:

The kangaroo was 1.164s in the air before returning to Earth

Explanation:

For this we are going to use the equation of distance for an uniformly accelerated movement, that is:

$x = x_{0} + V_{0}t + \frac{1}{2}at^2$

Where:

x = Final distance

xo = Initial point

Vo = Initial velocity

a = Acceleration

t = time

We have the following values:

x = 1.66m

xo = 0m (the kangaroo starts from the floor)

Vo = 0 m/s (each jump starts from the floor and from a resting position)

a = 9.8 m/s^2 (the acceleration is the one generated by the gravity of earth)

t =This is just the time it takes to the kangaoo reach the 1.66m, we don't know the value.

Now replace the values in the equation

$x = x_{0} + V_{0}t + \frac{1}{2}at^2$

$1.66 = 0 + 0t + \frac{1}{2}9.8t^2$

$1.66 = 4.9t^2$

$\frac{1.66}{4.9} = t^2$

$\sqrt{0.339} = t\\ t = 0.582s$

It takes to the kangaroo 0.582s to go up and the same time to go down then the total time it is in the air before returning to earth is

t = 0.582s + 0.582s

t = 1.164s

The kangaroo was 1.164s in the air before returning to Earth

5 0

3 years ago

What is the law of reflection?

tia_tia [17]

You can observe this law in practice if <span>a ray of light reflects off of a flat mirror.
</span>
Law of reflection states that both direction of both incoming and outgoing rays of light make the same angle with respect to surface normal.

4 0

3 years ago

Read 2 more answers

Part CPart complete Determine the maximum force P that can be applied without causing the two 43-kg crates to move. The coeffici

Wewaii [24]

Answer:

the maximum force will be equal to 134.84 N

Explanation:

We have given mass m = 43 kg

Coefficient of static friction $\mu _s=0.32$

Acceleration due to gravity $g=9.8m.sec^2$

We have to find the maximum force which , when applied there is no movement of crates

This maximum force will be equal to frictional force

Frictional force is given by $f=\mu mg=0.32\times 43\times 9.8=134.84N$

So the maximum force will be equal to 134.84 N

3 0

2 years ago

A car traveling on a level road initially has 440 kJ of mechanical energy. After the brakes are applied for a few seconds, the c

Anvisha [2.4K]

Answer:

Explanation:

Given that

There's a change in friction from 440 kJ to 110 kJ

This change is as a result of conversion of energy. The energy of the car system converted the mechanical energy in it, into a corresponding heat energy. During the course of this conversion, is where a whopping 330 kJ of energy went missing.

The 330 kJ of energy was lost as a result of the conversion of mechanical energy into heat energy by the use of friction.

3 0

2 years ago

A ball of mass m kg is rolled up a slope at an angle a to the horizontal, where sin a = 2/5. The ball passes a point A with spee

myrzilka [38]

16.42 seconds will elapse between passing B on the way up and coming back to B on the way down.

<h3>What is the definition of Angular Speed? </h3>

The rate of change of angular displacement is defined as angular speed, and it is stated as follows:

ω = θ t

Where,

θ is the angle of rotation,

t is the time

ω is the angular velocity

Given data;

sin a = 2/5

a=sin(2/5)

a=23°

The linear velocity is the product of the angular velocity and the length.

$\rm v= \omega r \\\\ \omega= 7/5 \\\\ \omega= 1.4 \ rad/sec$

The times between the two points are found as;

$\omega = \frac{\triangle \theta }{\triangle t} \\\\ t= \frac{23}{1.4} \\\\ t = 16.42 \ sec$

Hence, the time between passing B on the way up and returning to B on the way down will be 16.42 sec.

To learn more about the angular speed refer to the link;

brainly.com/question/9684874

#SPJ1

5 0

1 year ago