To calculate the length of the wire, we use formulas,
(A)
(B)
Here, R is the resistance of the wire, I is the current flows through wire and V is potential difference. A is cross sectional area of wire and is the density of copper wire and is value,.
Given
Substituting the values of I and V in equation (A ) we get,
Now from equation (B),
Therefore,
Thus the length of the copper wire is 177.9 m.
To solve this problem we will apply the concepts related to the Doppler effect. The relationship given between the observed frequency and the actual frequency is given under the following mathematical function,
Here,
Rearrange the equation to obtain the frequency observed
Therefore the frequency of the emergency lights that you observe when it reaches you in your spaceship is
The direction of the acceleration is the same as the direction of the net force: 34 degrees. Apply the equation <eq04017> to find the magnitude of the net force, giving you 35.4 N. Use the magnitude of the force and the mass to find the magnitude of the acceleration: a = F/m = (35.4 N)/(0.10 kg) = 354 m/s2.
Correct Answer: B optionPotential Difference = V = 200 V
Charge on the plate = Q =
C
Capacitance = C
Q, C and V for a parallel plate capacitor are related as:
Q = CV
⇒
C = Q/V
Using the values in the formula, we get:
F
Therefore, B option is the correct answer.
Answer:
a) I₂ = 2.78 10⁻² W / m²
, b) I₃ = 9 10⁻² W/m²
, c) R₄ = 2 10⁶ m
Explanation:
The intensity of a wave is defined as the emission power per unit area
I = P / A
The unit of decibels is defined by
β = 10 log (I / Io)
With Io the hearing threshold 10⁻¹² W / m²
a) the intensity at r = 12m
Let's use the first equation
P = IA
I₁ A₁ = I₂ A₂
Let's look for intensity (I₁)
β / 10 = log I₁ / I₀
I / I₀ =
I = I₀
I = 1 10⁻¹²
I = 1 W / m²
The area of a spherical surface is
A = 4π R²
I₁ r₁² = I₂ r₂²
I₂ = I₁ R₁² / r₂²
I₂ = I₁ 2²/12²
I₂ = 1 2.78 10⁻²
I₂ = 2.78 10⁻² W / m²
b) r = 21 m
I₃ = I₁ r₁² / r₃²
I₃ = 1 2²/21²
I₃ = 9 10⁻² W/m²
c) in this case I₄ = I₀
I₁ r₁² = I₄ r₄²
R₄² = I₁ / I₄ r₁²
R₄² = 1 / 10⁻¹² 2²
R₄² = 4 10¹²
R₄ = 2 10⁶ m