Answer:
Part a)

Part b)

Explanation:
Part a)
Level of sound = 75 dB
now we know that

here we know that

now we have


Part b)
Intensity of sound wave is given as

here we know that

so we have


now we know



now we have


Answer:
0.0814 Wb
Explanation:
L = length of the rectangular coil = 5 cm = 0.05 m
w = width of rectangular coil = 7 cm = 0.07 m
A = Area of the coil = L w = 0.05 x 0.07 = 35 x 10⁻⁴ m²
B = magnitude of uniform magnetic field = 0.55 T
θ = angle of axis of coil with magnetic field = 65°
Magnetic flux through the coil is given as
Φ = N B A Cosθ
Φ = (100) (0.55) (35 x 10⁻⁴ ) Cos65
Φ = 0.0814 Wb
Answer:

Explanation:
According to Coulomb's law, the magnitude of the force (F) between two objects with the same charge(+Q), separated a distance (d) apart, is defined as:

Here k is the Coulomb constant. The charge on each object is doubled, that is
:
