Answer:
43.16°
Explanation:
λ = Wavelength = 1.4×10⁻¹⁰ m
θ₁ = 20°
n can be any integer
d = distance between the two slits
Since for the first bright fringe, n₁ = 1
n₂ = 2 for second order line
The relation between the distance of the slits and the angle through which it is passed is:
dsinθ=nλ
As d and λ are constant

∴ Angle by which the second order line appear is 43.16°
Answer:
Positive
Explanation:
The leaves will diverge further: The positive charge on the leaves has increased further. This occurs when positive charge is produced on the leaves by the charged object. This is quite possible only when the object is positively charged.
Answer:
A
Explanation:
Objects with the same charge (Ex. North and north) repel each other.
Answer:
The telescope can gather light 1600 times more than the human eyes can!
Explanation:
The light gathering ability of an optical element is directly proportional to its area of opening.
So, in comparing the light gathering abilities for two objects, it is just the ratio of their area of opening.
Let the diameter of the telescope be D = 1 m
And the diameter of the human eyes be d = 2.5 cm = 0.025 m
Light gathering ability of the telescope compared to the eyes = D² ÷ d²
= (D²/d²) = (1²/0.025²) = 1600 times.
The telescope can gather light 1600 times more than the human eyes can!
Hope this Helps!!!