All categories

3 years ago

what is the focalength of the combination of two thin renses of power -5D and -2D placeci in contact with each other?

Physics

1 answer:

Ghella [55]3 years ago

6 0

Answer:

f = - 0.143 m = - 14.3 cm

Explanation:

First, we will calculate the power of the combination of lenses:

P = P₁ + P₂

where,

P = Power of Combination = ?

P₁ = Power of first lens = - 5D

P₂ = Power of second lens = - 2D

Therefore,

P = - 5D - 2D

P = - 7D

Now, the focal length can be given as:

$f = \frac{1}{P} \\\\f = \frac{1}{-\ 7\ D} \\\\$

Negative focal length indicates that combination will act as diverging lens.

You might be interested in

Which of the following are vector quantities? Select all that apply.

valkas [14]

Answer:

7 miles southwest

9 steps to the left

75 mph north

Explanation:

A vector quantity is any physical quantity that specifies the magnitude of the quantity and its direction.

So, the choices that gives a magnitude and direction are vectors.

The other type of physical quantities are the scalar which only specifies the magnitude but no direction;

9 steps to the left and 7 miles southwest are called displacement

75 mph north is velocity

8 0

3 years ago

The sound intensity from a jack hammer breaking concrete is 2.0W/m2 at a distance of 2.0 m from the point of impact. This is suf

kupik [55]

Answer:

(a) $I_{1}=3.2*10^{-3}W/m^{2}$

(b) $\beta =95dB$

Explanation:

Given data

Distance r₁=50 m

Distance r₂=2 m

Intensity I₂=2.0 W/m²

To find

(a) The Sound Intensity I₁

(b) The Sound Intensity level β

Solution

For (a) the Sound Intensity I₁

$\frac{I_{1} }{I_{2}}=\frac{(r_{2})^{2} }{(r_{1})^{2} }\\I_{1} =I_{2}(\frac{(r_{2})^{2} }{(r_{1})^{2} })\\I_{1}=(2.0W/m^{2} )(\frac{(2m)^{2} }{(50m)^{2} })\\I_{1}=3.2*10^{-3}W/m^{2}$

For (b) the Sound Intensity level β

The Sound Intensity level β is calculated as follow

$\beta =(10dB)log_{10}(\frac{I}{I_{o} } )\\\beta =(10dB)log_{10}(\frac{3.2*10^{-3}W/m^{2} }{1.0*10^{-12} W/m^{2} } )\\\beta =95dB$

8 0

3 years ago

Which will be attracted to (or repelled by) a magnet ?

Dima020 [189]

I believe it’s A C F

4 0

3 years ago

Read 2 more answers

Write the equation for eccentricity

Svetradugi [14.3K]

<span>e=ca{\displaystyle e={\frac {c}{a}}}.</span>

3 0

4 years ago

the primary of a transformer connected to 170v has 10 turns. the secondary has 70 turns. find voltage. this is a step down trans

Nikolay [14]

No it isn't. (Unless you connect it backwards.)

If the primary has 10 turns and the secondary has 70 turns,
then the voltage that appears across the secondary is
7 times the voltage that you feed to the primary.

If you're 'exciting' the primary with 170 volts, then you need
to be cautious around the secondary terminals, because there's
1,190 volts there !

If you want to use your transformer in a step-down configuration,
you can certainly connect it up the other way around.

Feed the 170 volts to the winding with 70 turns. You've reversed
the labels 'primary' and 'secondary', and that's OK. The voltage
at the terminals of the 10-turn winding will be (170/7) = 24.3 volts.

4 0

4 years ago

what is the focalength of the combination of two thin renses of power -5D and -2D placeci in contact with each other?​

what is the focalength of the combination of two thin renses of power -5D and -2D placeci in contact with each other?