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3 years ago

Multiple choice: Sunspots appear dark because

1 answer:

3 0

Answer: C. They are regions in which strong magnetic fields make it difficult for fresh supplies of hot, ionized gas to reach the photosphere

Explanation:

Sunspots appear dark because they are regions in which strong magnetic fields make it difficult for fresh supplies of hot, ionized gas to reach the photosphere.

Sunspots are typically cooler than their surroundings. For example, the temperature of a large sunspot can be about 4,000 Kelvin which is lower than the temperature of the photosphere around it which is about 5,800 Kelvin.

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Question for the day!

Alex17521 [72]

Answer:

1. <--> A.

2. <--> C.

3. <--> D

4. <--> B.

explanation: i know my science!

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3 years ago

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A 1060-kg car moving west at 16 m/s collides with and locks onto a 1830-kg stationary car. determine the velocity of the cars ju

iren [92.7K]

M1U1 + M2V2 = (M1+M2)V, where M1 is the mass of the moving car, M2 is the mass of the stationary car, U1 is the initial velocity, and V is the common velocity after collision.
therefore;
(1060× 16) + (1830 ×0) = (1060 +1830) V
16960 = 2890 V
V = 5.869 m/s
The velocity of the cars after collision will be 5.689 m/s

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3 years ago

Two long parallel wires 40 cm apart are carrying currents of 10 A and 20 A in the opposite direction. What is the magnitude of t

Alex_Xolod [135]

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;

$B = \frac{\mu _oI_1}{2 \pi r} + \frac{\mu_oI_2}{2\pi r}$

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

$B = \frac{\mu_o I_1}{2\pi r} + \frac{\mu_o I_2}{2\pi r} \\\\B = \frac{\mu_o }{2\pi r} (I_1 +I_2)\\\\B = \frac{4\pi *10^{-7} }{2\pi *0.2} (10 +20) = 3.0 *10^{-5}\ T$

Therefore, the magnitude of the magnetic field halfway between the wires is 3.0 x 10⁻⁵ T.

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3 years ago

If an element has a charge of 2+, how many more protons does it have than electrons?

yulyashka [42]

If an element has a charge of 2+, It has 2 more proton than electrons

6 0

3 years ago

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A gray kangaroo can bound across a flat stretch of ground with each jump carrying it 10 m from the takeoff point. you may want t

Stells [14]

Answer:

Takeoff speed of Kangaroo = 12.91 m/s

Explanation:

The distance reached by Kangaroo = 10 meter

Angle at which it jumps = 18°

The motion of Kangaroo is like a projectile, the distance traveled is the range of projectile.

Range of projectile = Time taken for the projectile to reach ground* Horizontal velocity

Time taken for the projectile to reach ground:

Time taken = Two times of the time taken for the projectile to reach maximum height

Time taken for the projectile to reach maximum height = Vertical speed / Acceleration = u sin θ/g

Time taken for the projectile to reach ground = 2 u sin θ/g

So Range of projectile = $ucos\theta*\frac{2usin\theta}{g} =\frac{u^2sin2\theta}{g}$

We have Range = 10 meter, θ = 18⁰

Substituting

$10=\frac{u^2sin(2*18)}{9.8}\\ \\ u^2= 166.73\\ \\ u=12.91 m/s$

Takeoff speed of Kangaroo = 12.91 m/s

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3 years ago

Read 2 more answers