Sound intensity is inversely proportional to the square of the distance between the source and the receiver.
That is
I = k/r^2
where
k = constant
r = radius
When r=1, the intensity is I₁ = k/1 = k
When r=3, the intensity I₂ = k/3² = k/9
Therefore
I₂ = I₁ /9
In decibels,
I = 10 log₁₀(I/I₀)
where I₀ = reference intensity
When r=1,
10 log₁₀ (I₁/I₀) = 270
When r =3,
10 log₁₀ (I₂/I₀) = 10 log₁₀ [(I₂/I₁)*(I₁/I₀)]
= 10 log₁₀ [(1/9)*(I₁/I₀)]
= 10 log₁₀(1/9) + 270
= 260.5
Answer: 260.5 dB (nearest tenth)
The ability to attract electrons is called electronegativity.
Answer:
The acceleration of the sliding toboggan is, a = 4.9 m/s²
Explanation:
Given data,
The total weight of the toboggan, W = 1300 N
The slope is, Ф = 30°
The acceleration of a body under the influence of the gravitational field does not depend on its mass, size and shape in the absence of the air resistance.
Therefore,
The acceleration of the toboggan is given by the formula,
a = g Sin Ф
Substituting the given values in the above equation,
a = 9.8 x Sin 30°
= 4.9 m/s²
Hence, the acceleration of the sliding toboggan is, a = 4.9 m/s²
Options (b) and (d) are correct about an electric motor.
An electric motor is a device which coverts electrical energy into mechanical energy.It works on the principle that when a current carrying coil is placed in a magnetic field, it experiences torque. Because of that torque, the coil rotates and thus the electrical energy gets converted into mechanical (motion) energy.
D. A magnetic field created by the electric current causes the compass needle to move.
