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2 years ago

If a 72-candela light source is located at a distance of 3 meters from a surface, the illuminance on the surface is

1 answer:

8 0

If a 72-candela light source is located at a distance of 3 meters from a surface, the illuminance on the surface is _____.

The formula of illuminance is equal to:
Illuminance = distance * light
Illuminance = 3 * 72
<span>Illuminance = 216 lux.

So the correct answer is letter (A) 216 lux.</span>

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A capacitor with an initial potential difference of 185 V is discharged through a resistor when a switch between them is closed

GrogVix [38]

Answer:

a. $\tau = 2.1161 s$

b. $V(18.8 \ s) = 0.0256 \ V$

Explanation:

The equation for the voltage V of discharging capacitor in an RC circuit at time t is:

$V(t) = V_0 e^{(- \frac{t}{\tau}) }$

where $V_0$ is the initial voltage, and $\tau$ is the time constant.

For our problem, we know

$V_0 = 185 \ V$

and

$V(10 \ s) = V_0 e^{(- \frac{10 \ s}{\tau}) } = 1.64 \ V$

$185 \ V \ e^{(- \frac{10 \ s}{\tau}) } = 1.64 \ V$

$e^{(- \frac{10 \ s}{\tau}) } = \frac{1.64 \ V}{ 185 \ V }$

$ln (e^{(- \frac{10 \ s}{\tau}) } ) = ln (\frac{1.64 \ V}{ 185 \ V })$

$- \frac{10 \ s}{\tau} = ln (\frac{1.64 \ V}{ 185 \ V })$

$\tau = \frac{-10 \s}{ln (\frac{1.64 \ V}{ 185 \ V }) }$

This gives us

$\tau = 2.1161 s$

and this is the time constant.

At t = 18.8 s we got:

$V(18.8 \ s) = 185 \ V \ e^{(- \frac{18.8 \ s}{2.1161 s}) }$

$V(18.8 \ s) = 0.0256 \ V$

4 0

3 years ago

If you are building a house, which type of windows would you install in your bathroom so that you can have lots of light but pri

amm1812

A. Translucent because it’s shows a little light on the inside and looks dark on the outside

5 0

3 years ago

Which scientist is often called the “father of the atomic bomb” because of his work as the head of the manhattan project?

kirza4 [7]

Answer:

J. Robert Oppenheimer

Explanation:

He led the Manhattan project and created the first nuclear bomb in WWII

8 0

3 years ago

A current runs to the right in a long, straight wire. What is the direction of the

SIZIF [17.4K]

Answer:

Into the page (Answer B)

Explanation:

Recall that the magnetic field that is created around a current conducting wire follows the right hand rule, where the direction of your fingers point in the direction of the magnetic field vectors when your thumb points in the direction of the current flow.

Use this to see that as you place the thumb of your right hand on the page pointing to the right (direction of the current in the wire). As you do so, you find the four fingers of your right hand entering the paper.

7 0

2 years ago

A measure of the disorder of a system is called:<br> enthalpy<br> energy<br> entropy<br> synergy

Gre4nikov [31]

The answer is Entropy or part C.

Entropy is basically a thermodynamic quantity that tells the randomness of a system or as said in the question tells us a measure of the disorder of the system.

The second law of thermodynamics states that a closed system has entropy which may remain constant or otherwise might increase.

It is basically the measure of the change of a system or universe when it goes from order to disorder.

5 0

2 years ago