A person next to a fireplace feels warm. How is the heat transferred to them?

Joseph studied whether different materials can block certain electromagnetic waves by testing television reception in different

gizmo_the_mogwai [7]

Using the same antenna. Now he doesn't know if it was the antenna that caused the change in reception. so he wasn't only measuring the reception in his house he was measuring it based on different antennas

7 0

2 years ago

A 40 cm wire with a radius of 3 cm is oriented along the y axis and carries a current of 2 A. What is the magnitude of the magne

ZanzabumX [31]

Answer:

a) B = 1.99 x 10⁻⁴ Tesla

b) B = 0.88 x 10⁻⁴ Tesla

Explanation:

According to Biot - Savart Law, the magnetic field due to a currnt carrying straight wire is given as:

B = μ₀ I L/4πr²

where,

μ₀ = permebility of free space = 1.25 x 10⁻⁶ H m⁻¹

I = current = 2 A

L = Length of wire = 40 cm = 0.4 m

a)

r = radius of magnetic field = 2 cm = 0.02 m

Therefore,

B = (1.25 x 10⁻⁶ H m⁻¹)(2 A)(0.4 m)/4π(0.02 m)²

B = 1.99 x 10⁻⁴ Tesla

b)

r = radius of magnetic field = 3 cm = 0.03 m

Therefore,

B = (1.25 x 10⁻⁶ H m⁻¹)(2 A)(0.4 m)/4π(0.03 m)²

B = 0.88 x 10⁻⁴ Tesla

7 0

3 years ago

Infrared waves from the sun are what make our skin feel warm on a sunny day. If an infrared wave has a frequency of 3.0 x 1012 H

djyliett [7]

Answer:

The wavelength of the infrared wave is 0.0001 m.

Explanation:

Given:

Frequency of an infrared wave is, $f=3.0\times 10^{12}\ Hz$

We know that, infrared waves are electromagnetic waves. All electromagnetic waves travel with the same speed and their magnitude is equal to the speed of light in air.

So, speed of infrared waves coming from the Sun travels with the speed of light and thus its magnitude is given as:

$v=c=3.0\times 10^8\ m/s$

Where, 'v' is the speed of infrared waves and 'c' is the speed of light.

Now, we have a formula for the speed of any wave and is given as:

$v=f\lambda$

Where, $\lambda \to \textrm{Wavelength of infrared wave}$

Now, rewriting the above formula in terms of wavelength, $\lambda$ , we get:

$\lambda=\dfrac{v}{f}$

Now, plug in $3.0\times 10^8$ for 'v', $3.0\times 10^{12}$ for 'f' and solve for $\lambda$ . This gives,

$\lambda=\frac{3.0\times 10^8}{3.0\times 10^{12}}\\\\\lambda=0.0001\ m$

Therefore, the wavelength of the infrared wave is 0.0001 m.

5 0

3 years ago

1. Define weight

andrezito [222]

1. Weight is the gravitational pull with which the earth attracts the body towards the center of the earth. The S.I unit is Newton (N)

2. The weight of an object is related to its mass with the below equation.

W = mg

Where W = weight, m = mass and g = acceleration due to gravity

3. The mass m = 50 kg and g = 9.8 m/ $s^{2}$

Substitute the parameters in the equation above.

W = 50 x 9.8

W = 490 N

4. An object is accelerating when it speeds up. If the object slows down, it means it is decelerating. The correct answer is option A

5. Newton's second law of motion is:

F = ma

Where F = force applied, m = mass and a = acceleration

Therefore, Newton's second law of motion relates an object's acceleration to its net force acting on it. The correct answer is option C

6. According to Newton's second law of motion which relates an object's acceleration to its mass, doubling the net force acting on an object a doubles its acceleration. Because mass is always constant.

7. Since the weight of an object is related to its mass with the equation.

W = mg, If the mass of an object doubles, its weight will also doubles. Option A is the correct answer.

8. If you know the mass of an object, you can calculate its weight with the formula F = mX when X = 9.8m/ $s^{2}$

9. Force is expressed in unit as Newton (N)

10. The parameters given are :

mass m = 20kg

Force F = 40N

To calculate acceleration, use the formula F = ma

Substitute all the parameters into the equation.

40 = 20a

a = 40/20

a = 2m/ $s^{2}$

The correct option is D

Learn more here : brainly.com/question/18835375

8 0

3 years ago

A scientist designs an experiment in which a light source is pointed at a substance and a light detector is placed on the opposi

Lostsunrise [7]

The answer is D. Either absorbed or reflected. The reason is because if no light is being shown on the other side, the substance is not letting any light pass through. Since we do not know anything else about the substance, we do not know which one of the two it is doing. The scientist would not see any light on the detector if 100% of the light is reflected and the same thing would happen if 100% of the light was absorbed.

5 0

2 years ago

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