Aluminium has a work function of 4. 08 eV. The cutoff wavelength and cutoff frequency for the photoelectric effect is 303.9nm and 911.7× 10¹⁷ s⁻¹ respectively.
Work Function is the minimum energy required to eject an electron from a photoelectric material.
Cutoff Wavelength is the maximum wavelength below which electron will be ejected
Cutoff Frequency is the minimum frequency required to eject electron.
Let the work function of Aluminium be Φ
Given, work function Φ = 4.08eV
We know that hc/λ = Φ
where, h is Planck constant
c is speed of light
λ is wavelength of light used
Hence, on subsitution
1240 / λ = 4.08 eV (hc = 1240)
⇒ λ = 303.9 nm
Hence, cutoff wavelength used is 303.9 nm
We know that ν = c/λ
ν = 3 × 10⁸ / 303.9
⇒ ν = 911.7 × 10¹⁷ s⁻¹
Hence, cutoff frequency used is 911.7 × 10¹⁷ s⁻¹
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Answer:
The correct option is 'd': The change in shape of an object.
Explanation:
Since by definition physical change is defined as a change that changes only the form of an object or substance and producing no change in the chemical composition of the substance. Physical changes are reversible in nature.
As we can see from all the options the change in the shape of the object is a reversible change as we can always remold any substance in any shape, thus it confirms to a physical change.
The change in the molecular composition of an object is a hallmark of a chemical reaction thus indicates a chemical change.
The smell change in an object is an indication of a chemical change in the object hence is not a physical change.
Well if the rock doesn't move, then there is no amount of work done. There is no work done on an object if a force is applied to the object but it DOES NOT change its position, in this case is the rock.
Answer:
Explanation:
If Ek is the kinetic energy and m is the mass and v is the velocity then v can be calculated as follows
Ek= 1/2 ×( m × v² )
2Ek= mv²
2Ek/m = v²
v =√(2Ek/m)
m = 0.1 kg
v= √(2x8/0.1)= 12.65 m/s
<span>Subrahmanyan Chandrasekhar
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