Heat transfer that doesn’t need a medium? A) Radiation B)Convection C)Conduction

2 answers:

8 0

Radiation is a method of heat transfer through electromagnetic waves. This transfer does not require a medium in order for heat to be transferred.

The solution is A.

Rufina [12.5K]3 years ago

6 0

The correct answer is A

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A 50-ω resistor is connected to a 9.0 V battery. How much thermal energy is produced in 7.5 minutes?1.2 * 10^2 J1.3 * 10^3 J3.0

emmasim [6.3K]

In order to calculate the thermal energy, first let's calculate the power, using the formula:

$P=\frac{V^2}{R}$

For a voltage V = 9 Volts and a resistance R = 50 ohms, we have:

$\begin{gathered} P=\frac{9^2}{50} \\ P=\frac{81}{50}=1.62\text{ W} \end{gathered}$

Now, multiplying the power by the time (in seconds), we can find the energy:

$\begin{gathered} E=P\cdot t \\ E=1.62\cdot7.5\cdot60 \\ E=729\text{ J} \end{gathered}$

In scientific notation, we have an energy of 7.3 * 10^2 J, therefore the correct option is the fourth one.

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11 months ago

Ball 1, with a mass of 100 g and traveling at 10 m/s, collides head-on with ball 2, which has a mass of 300 g and is initially a

qaws [65]

There is 4000 balls in the earth of the world why is that so hard for you

5 0

1 year ago

Kon'nichiwa~<br>please help me with this question!!

andrezito [222]

Let's check the relationship

$\\ \rm\hookrightarrow g=\dfrac{GM}{r^2}$

$\\ \rm\hookrightarrow g\propto G$

Raindrops will fall faster . .
Also walking on ground would become more difficult as g increases.

Option C is wrong by now .Let's check D once

$\\ \rm\hookrightarrow T\propto \dfrac{1}{\sqrt{g}}$

So time period of simple pendulum would decrease.

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2 years ago

if a torque of 55.0 N/m is required and the largest force that can be exerted by you is 135 N what is th e length of the lever a

Whitepunk [10]

Answer:

$r=0.41m$

Explanation:

Torque is defined as the cross product between the position vector ( the lever arm vector connecting the origin to the point of force application) and the force vector.

$\tau=r\times F$

Due to the definition of cross product, the magnitude of the torque is given by:

$\tau=rFsin\theta$

Where $\theta$ is the angle between the force and lever arm vectors. So, the length of the lever arm (r) is minimun when $sin\theta$ is equal to one, solving for r: