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2 years ago

A long, straight, cylindrical wire of radius R carries a current uniformly distributed over its cross section.

Physics

1 answer:

Mice21 [21]2 years ago

3 0

Answer:

Explanation:

We shall solve this question with the help of Ampere's circuital law.

Ampere's ,law

∫ B dl = μ₀ I , B is magnetic field at distance x from the axis within wire

we shall find magnetic field at distance x . current enclosed in the area of circle of radius x

= I x π x² / π R²

= I x² / R²

B x 2π x = μ₀ x current enclosed

B x 2π x = μ₀ x I x² / R²

B = μ₀ I x / 2π R²

Maximum magnetic B₀ field will be when x = R

B₀ = μ₀I / 2π R

Given

B = B₀ / 3

μ₀ I x / 2π R² = μ₀I / 2π R x 3

x = R / 3

b ) The largest value of magnetic field is on the surface of wire

B₀ = μ₀I / 2π R

At distance x outside , let magnetic field be B

Applying Ampere's circuital law

∫ B dl = μ₀ I

B x 2π x = μ₀ I

B = μ₀ I / 2π x

Given B = B₀ / 3

μ₀ I / 2π x = μ₀I / 2π R x 3

x = 3R .

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Find the resistance of an electric light bulb if a current of 0.08 A flows when the potential difference across the bulb is 120

lora16 [44]

U=RI Ohm's law
then R=U/I
=120/0.08
=2250Ω
hope this helps you

8 0

3 years ago

A 5.93 kg ball is attached to the top of a vertical pole with a 2.35 m length of massless string. The ball is struck, causing it

Delvig [45]

Answer

given,

mass of ball = 5.93 kg

length of the string = 2.35 m

revolve with velocity of 4.75 m/s

acceleration due to gravity = 9.81 m/s²

T cos θ = mg

T cos θ = $5.93\times 9.81$

T cos θ = 58.17

$T sin \theta =\dfrac{mv^2}{r}$

$T sin \theta =\dfrac{5.93\times 4.75^2}{2.35 sin \theta}$

$T sin^2 \theta =56.93$

$sin^2 \theta = 1 - cos^2 \theta$

$T (1 - cos^2 \theta) =56.93$

$T (1 - (\dfrac{58.17}{T})^2) =56.93$

T² - 56.93T - 3383.75 = 0

T = 93.22 N

$cos \theta = \dfrac{58.17}{93.22}$

θ = 51.39°

6 0

3 years ago

A 12.0-g bullet is fired horizontally into a 109-g wooden block that is initially at rest on a frictionless horizontal surface a

kykrilka [37]

Answer:

v₀ = 280.6 m / s

Explanation:

we have the shock between the bullet and the block that we can work with at the moment and another part where the assembly (bullet + block) compresses a spring, which we can work with mechanical energy,

We write the mechanical energy when the shock has passed the bodies

Em₀ = K = ½ (m + M) v²

We write the mechanical energy when the spring is in maximum compression

$Em_{f} = K_{e} \\= \frac{1}{2} kx^2\\ Em_0 = Em_{f}$

½ (m + M) v² = ½ k x²

Let's calculate the system speed

v = √ [k x² / (m + M)]

v = √[152 ×0.78² / (0.012 +0.109) ]

v = 27.65 m / s

This is the speed of the bullet + Block system

Now let's use the moment to solve the shock

Before the crash

p₀ = m v₀

After the crash

$p_{f} = (m + M) v$

The system is formed by the bullet and block assembly, so the forces during the crash are internal and the moment is preserved

$p_0 = p_{f}$

m v₀ = (m + M) v

v₀ = v (m + M) / m

let's calculate

v₀ = 27.83 (0.012 +0.109) /0.012

v₀ = 280.6 m / s

4 0

2 years ago

The energy generated by the sun travels to Earth as electromagnetic waves of varying lengths. Which statement describes an elect

Paha777 [63]

Answer: 4(45)

Explanation:

It’s not equal

3 0

2 years ago

Read 2 more answers

An object is floating in equilibrium on the surface of a liquid. The object is then removed and placed in another container, fil

Anestetic [448]

Answer:

The fraction of its volume inside liquid is increased .

Explanation:

According to principle pf floatation , an object floats on the surface of water

when the weight of liquid displaced by it becomes equal to weight of the object . weight of the liquid depends upon the density of the liquid .

In the second case , when the body is dipped into liquid of lesser density , in order to balance the weight of body , more volume of liquid will be displaced so that weight of displaced liquid becomes equal to object's weight . So the body floats with greater depth inside liquid . The fraction of its volume inside liquid is increased .

4 0

2 years ago