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kenny6666 [7]
3 years ago
11

suppose that you look into a photometer's eyepiece and the fluorescent disks appear to be equal in intensity. If the distance be

tween the photometer to lamp 1 is 400mm, the distance between the photometer to lamp 2 is 200 mm, and the intensity of lamp 2 is known to be 15 candelas, what is the intensity to lamp 1?
Physics
1 answer:
d1i1m1o1n [39]3 years ago
7 0
Use the Inverse square law, Intensity (I) of a light is inversely proportional to the square of the distance(d).

I=1/(d*d)

Let Intensity for lamp 1 is L1 distance be D1 so on, L2 D2 for Intensity for lamp 2 and its distance.

L1/L2=(D2*D2)/(D1*D1)

L1/15=(200*200)/(400*400)
L1=15*0.25
L1=3.75 <span>candela</span>

You might be interested in
According to the concept of length contraction, what happens to the length of an object as it approaches the speed of light and
lord [1]
When an object moves its length contracts in the direction of motion. The faster it moves the shorter it gets in the direction of motion.
The object in this question moves and then stops moving. So it's length first contracts and then expands to its original length when the motion stops.
The speed doesn't have to be anywhere near the speed of light. When the object moves its length contracts no matter how fast or slow it's moving.
8 0
4 years ago
What is the force of a object that has a mass of 7 kg and an acceleration of 6 m/s/s
UkoKoshka [18]

Answer:

<h2>42 N</h2>

Explanation:

The force acting on an object given it's mass and acceleration can be found by using the formula

force = mass × acceleration

From the question

mass = 7 kg

acceleration = 6 m/s²

We have

force = 7 × 6 = 42

We have the final answer as

<h3>42 N</h3>

Hope this helps you

7 0
3 years ago
Suppose that the Mars orbiter was to have established orbit at 155 km and that one group of engineers specified this distance as
MAXImum [283]

Answer:

108 km

Explanation:

The conversion factor between meters and feet is

1 m = 3.28 ft

So the second altitude, written in feet, can be rewritten in meters as

h_2 = 1.55 \cdot 10^5 ft \cdot \frac{1}{3.28 ft/m}=4.7\cdot 10^4 m

or in kilometers,

h_2 = 47 km

the first altitude in kilometers is

h_1 = 155 km

so the difference between the two altitudes is

\Delta h = 155 km - 47 km = 108 km

8 0
3 years ago
A circle has an initial radius of 50ft when the radius begins decreasing at a rate of 2ft/s. what is the rate of change of the a
valkas [14]
The area of the circle with radius r is
A = πr²

The rate of change of area with respect to time is
\frac{dA}{dt} = \frac{dA}{dr} . \frac{dr}{dt} =2 \pi r. \frac{dr}{dt}

The rate of change of the radius is given as
\frac{dr}{dt} =-2 \,  \frac{ft}{s}
Therefore
\frac{dA}{dt} =-4 \pi r \,  \frac{ft^{2}}{s}

When r = 10 ft, obtain
\frac{dA}{dt}|_{r=10 \, ft} = -40 \pi  \,  \frac{ft^{2}}{s}

Answer: - 40π ft²/s (or - 127.5 ft²/s)
7 0
4 years ago
How would you determine how much error there is between a vector addition and the real results
chubhunter [2.5K]
Desired operation: A + B = C; {A,B,C) are vector quantities. 

<span>Issue: {A,B} contain error (measurement or otherwise) </span>

<span>Objective: estimate the error in the vector sum. </span>

<span>Let A = u + du; where u is the nominal value of A and du is the error in A </span>
<span>Let B = v + dv; where v is the nominal value of B and dv is the error in B </span>
<span>Let C = w + dw; where w is the nominal value of C and dw is the error in C [the objective] </span>

<span>C = A + B </span>

<span>w + dw = (u + du) + (v + dv) </span>

<span>w + dw = (u + v) + (du + dv) </span>

<span>w = u+v; dw = du + dv </span>

<span>The error associated with w is the vector sum of the errors associated with the measured quantities (u,v)</span>
6 0
3 years ago
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