Answer:
M = 222 fringes
Explanation:
given
λ = 559 n m = 559 × 10⁻⁹ m
radius = 0.026 mm = 0.026 ×10⁻³ m
length of the glass plate = 22.1 ×10⁻² m
using relation


= 221.79
= 221 (approx.)
hence no of bright fringe
M = m + 1
= 221 +1
M = 222 fringes
The speed of the snail is given by:

where S is the distance covered by the snail and t the time taken.
The snail in the problem moves by S=18 mm in t=24 s, therefore its speed is

Answer:
The magnitude of the magnetic field halfway between the wires is 3.0 x 10⁻⁵ T.
Explanation:
Given;
distance half way between the parallel wires, r = ¹/₂ (40 cm) = 20 cm = 0.2 m
current carried in opposite direction, I₁ and I₂ = 10 A and 20 A respectively
The magnitude of the magnetic field halfway between the wires can be calculated as;

where;
B is magnitude of the magnetic field halfway between the wires
I₁ is current in the first wire
I₂ is current the second wire
μ₀ is permeability of free space
r is distance half way between the wires

Therefore, the magnitude of the magnetic field halfway between the wires is 3.0 x 10⁻⁵ T.
Water bottle and a paper towel role