The number of protons determines the element. Many elements also have many isotopes. Such as carbon-14 Carbon-12 and carbon-10.
Answer:
Part a)

Part b)

Part c)


Explanation:
Part a)
As we know that frequency = 1 MHz
speed of electromagnetic wave is same as speed of light
So the wavelength is given as



Part b)
As we know the relation between electric field and magnetic field



Part c)
Intensity of wave is given as



Pressure is defined as ratio of intensity and speed


<u>Answer</u>
1) A. 96 Candelas
2) A. Both of these types of lenses have the ability to produce upright images.
3) C. 5 meters
<u>Explanation</u>
Q1
The formula for calculation the luminous intensity is;
Luminous intensity = illuminance × square radius
Lv = Ev × r²
= 6 × 4²
= 6 × 16
= 96 Candelabra
Q2
For converging lenses, an upright image is formed when the object is between the lens and the principal focus while a diverging lens always forms and upright image.
A. Both of these types of lenses have the ability to produce upright images.
Q3
Luminous intensity = illuminance × square radius
square radius = Luminous intensity/ illuminance
r² = 100/4
= 25
r = √25
= 5 m