Which change decreases the resistance of a piece
1 answer:
Explanation :
We know that the resistance of the wire is given by :
Where
is the resistivity
l is the length of the wire
A is the area of the wire.
Another factor on which the resistance of wire depends is temperature. It is given by :
So, it is clear that the resistance of the wire is directly proportional to the temperature. It we want to decrease the resistance of the piece, its temperature should be decreased.
So, the correct option is (3) " decreasing the wire’s temperature ".
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Answer:
Second order line appears at 43.33° Bragg angle.
Explanation:
When there is a scattering of x- rays from the crystal lattice and interference occurs, this is known as Bragg's law.
The Bragg's diffraction equation is :
.....(1)
Here n is order of constructive interference, λ is wavelength of x-ray beam, d is the inter spacing distance of lattice and θ is the Bragg's angle or scattering angle.
Given :
Wavelength, λ = 1.4 x 10⁻¹⁰ m
Bragg's angle, θ = 20°
Order of constructive interference, n =1
Substitute these value in equation (1).
d = 2.04 x 10⁻¹⁰ m
For second order constructive interference, let the Bragg's angle be θ₁.
Substitute 2 for n, 2.04 x 10⁻¹⁰ m for d and 1.4 x 10⁻¹⁰ m for λ in equation (1).
<em>θ₁ </em>= 43.33°