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NeTakaya
3 years ago
12

a certain projetor uses a concave mirror for projecting an object's image on a screen .it produces on image that is 4 times bigg

er than the object and the screen is 5 m away from the mirror as shown in fig 5.2, calculate the focal length of the mirror.​
Physics
1 answer:
IrinaK [193]3 years ago
6 0

Answer:

f = 1 m

Explanation:

The magnification of the lens is given by the formula:

M = \frac{q}{p}

where,

M = Magnification = 4

q = image distance = 5 m

p = object distance = ?

Therefore,

4 = \frac{5\ m}{p}\\\\p = \frac{5\ m}{4}\\\\p = 1.25\ m

Now using thin lens formula:

\frac{1}{f}=\frac{1}{p}+\frac{1}{q}\\\\\frac{1}{f} = \frac{1}{1.25\ m}+\frac{1}{5\ m}\\\\\frac{1}{f} = 1\ m^{-1}\\\\

<u>f = 1 m</u>

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Suppose a conducting rod is 52 cm long and slides on a pair of rails at 2.75 m/s. What is the strength of the magnetic field in
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Answer:

5.6 Tesla

Explanation:

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e = 8 V

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e = B × V × L

B = e / V L

B = 8 / (2.75 × 0.52)

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3 years ago
The 10-kg block is held at rest on the smooth inclined plane by the stop block at A. If the10-g bullet is traveling at 300m/swhe
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Answer:

6.8 mm

Explanation:

We are given that

Mass of block,m=10 kg

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Speed of bullet,u=300 m/s

\theta=30^{\circ}

By law of conservation of momentum

m_bucos\theta=Mv

v=\frac{m_bvcos\theta}{M}=\frac{0.01\times 300cos30^{\circ}}{10.01}=0.259m/s

According to law of conservation of energy

Change in kinetic energy of system=Change in potential energy of system

\frac{1}{2}Mv^2-0=Mgh-0

\frac{1}{2}(10.01)(0.259)^2=10.01\times 9.8 h

Where g=9.8 m/s^2

h=\frac{(0.259)^2}{2\times 9.8}=0.0034m

1m=100 cm

h=0.0034\times 100=0.34 cm

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4 0
4 years ago
You have a perfectly circular apple pie with a radius of 15cm. You cut the pie into 12 approximately equal slices. What is the a
Sedaia [141]

Answer:

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30 degree

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As we know that that the angular displacement in one turn is 360 degree.

As there are 12 parts which are equally divided so the angle turn by each part is

= 360 / 12 = 30 degree

Thus, the angular displacement of each slice is 30 degree.

Radius of pie = 15 cm

Circumference of pie = 2 x 3.14 x 15 = 94.2 cm

Arc length for complete 360 degree = 94.2 cm

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4 years ago
A solid steel sphere of density 7.86 g/cm3 and mass 1 kg spin on an axis through its center with a period of 2.3 s. given vspher
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<span>The solution for this problem is:</span>

density = mass / volume <span>
7860 = 1 / ((4/3) pi r^3) 
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= (2/5) x 1 x 0.067^2

= 0.0017956 kg-m^2 <span>

1/2.3 = 0.4348 rev/s 

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Angular momentum = Inertia x rad/s 

0.0017956 x 2.732 = 0.00490557 kg m^2/s</span>

4 0
3 years ago
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