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Grade 12 Alternate E-Day Task (Photons and Electrons)

Last updated 10 months ago
28 questions
Note from the author:
This task will take you through the topic on electrons and photons. It forms part of your course work as outlined in the IEB SAGS document.
Watch the videos and answer the questions that follow.
This is a timed assignment and must be completed in one sitting.
This task will take you through the topic on electrons and photons. It forms part of your course work as outlined in the IEB SAGS document.
Watch the videos and answer the questions that follow.
This is a timed assignment and must be completed in one sitting.
Electromagnetic Waves
Required
1

Which electromagnetic radiation (EMR) was discovered by placing a thermometer next to the red light?

Required
1

The greater the frequency of the EMR, the smaller its wave.

Required
1
Which radio waves are the most damaging?_____________________
Other Answer Choices:
Microwaves
Radio waves
Ultraviolet rays
The Photoelectric Effect
The following video demonstrates the Photoelectric effect using visible light and UV Light.
Required
1

What metal is placed on the electroscope?

Required
1

The plate has to be negatively charged.

Required
2

Match the correct observations. Drag the observation to the correct light source.

Draggable itemCorresponding Item
gold leave drops
UV Light
gold leave remains in upright position
visible light from the desk lamp
Required
1

The brightness of the visible light will cause the gold leave to drop.

Required
1

One photon of light releases

1
Visible light unable to release an electron from the metal in the demonstration because it has _______ energy than a photon of UV light.
Watch the following video on the basic concepts involved in the photoelectric effect.
Answer the questions according to the time stamps on the video.
2

Describe the photoelectric effect.

2

Define threshold frequency (cut-off frequency).

2

Define work function of a metal.

Untitled Section
Watch the following video on the basic concepts involved in the photoelectric effect.
Answer the questions according to the time stamps on the video.

You may begin viewing at time: 10:44 (first marker on the video time line)
1

What metal is placed on the electrode?

1

What was the wavelength of the incident waves when the first observed electrons moved away from the cathode? Write down the value(number) only using ? (unit is nm)

1

Use the formula
to determine the frequency in Hz of this incident radiation. write down the value only.

3
Use the equation above to match the correct options with each term. E ______________________ = Wo______________________ + Ek______________________
Other Answer Choices:
pertains to the photo electron
Energy of photon
Energy required by a metal to release an electron
1

If the frequency of incident radiation is
Hz, calculate the energy carried by one photon of this light ?

2

Explain what is meant by the photoelectric effect.

1

How does an increasing the intensity of light affect the current in the circuit. Assume the light has a frequency greater than the threshold frequency. (increase, decrease, remains unchanged)

1

Are electrons ejected from a metal when the the incident radiation is below the threshold frequency? (yes/No)

1

Which metal is placed on the cathode now?

1

Why does this metal require a greater frequency of incident radiation to cause electrons to be ejected ?

1

What maximum wavelength is required to eject electrons from this metal

Watch video until 25:20
1

What does an increase in intensity of incident radiation produce before it strikes the metal?

Watch the video to the end.
Untitled Section
The Duality of Light: Is a light a wave or is it a particle? Watch the video below and answer the question that follow.
2

Light is made up of

Required
1

What other name is give to the "wave packets" of light?

Required
1

What field of physics did this discovery by Albert Einstein open up?

Activity 9.1 in your workbook page 274
1

Complete Activity 9.1 in your workbook page 274 and upload your answers