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zzz [600]
3 years ago
5

What is principal focus and focus length with examples​

Physics
1 answer:
Shkiper50 [21]3 years ago
7 0

Explanation:

Principle focus is the point on the axis of a convex lens, where the parallel rays of light from one side of the lens. meet on other side after refraction. Distance between optical centre to principle focus point is the focal length.

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IMPORTANT 3 QUESTIONS!
Brums [2.3K]

Answer:

7. 20,000,000 mL.

8. 8,000 m.

9. 120,000 secs.

10. 4

Explanation:

7. Determination of the volume in millilitres (mL)

Volume in litre (L) = 20,000 L

Volume in millilitres (mL) =..?

The volume in mL can be obtained as follow:

1 L = 1,000 mL

Therefore,

20,000 L = 20,000 x 1,000 = 20,000,000 mL.

Therefore, 20,000 L is equivalent to 20,000,000 mL.

8. Determination of the distance in metre (m)

Distance in mile = 5 mile

Distance in metre =?

First, we shall convert from mile to kilometre.

This can be done as follow:

1 mile = 1.6 km

Therefore,

5 mile = 5 x 1.6 = 8 km

Finally, we shall convert 8 km to metre (m).

This is illustrated below:

1 km = 1,000 m

Therefore,

8 km = 8 x 1,000 = 8,000 m

Therefore, 5 miles is equivalent to 8,000 m.

9. Determination of the time in seconds.

Time = 400 minutes for 5 days.

First, we shall convert 400 mins to hour.

This is illustrated below:

60 minutes = 1 hour

Therefore,

400 mins = 400/60 = 20/3 hours

The time (hours) is 20/3 hours in 1 day.

Therefore, the time (hours) in 5 days will be = 20/3 x 5 = 100/3 hours.

Next, we shall convert 100/3 hours to minutes.

This is illustrated below:

1 hour = 60 minutes

Therefore,

100/3 hours = 100/3 x 60 = 2000 mins

Finally, we shall convert 2000 mins to seconds.

This is illustrated below:

1 mins = 60 secs

2000 mins = 2000 x 60 = 120,000 secs.

Therefore, the time is 120,000 secs.

10. Determination of the number of significant figures.

To obtain the significant figures of a number, we simply count all the numbers available.

Therefore, the number of significant figures for 9876 is 4.

6 0
3 years ago
Which two criteria are least important for engineers to consider when developing a process to produce sulfur trioxide? A. The pr
VikaD [51]

Answer: it should be c and d

Explanation:

4 0
3 years ago
Read 2 more answers
During electrical storms, a bolt of lightning can transfer 10 C of charge in 2.0 µs (the amount of time can vary considerably).
nydimaria [60]

Answer:

Explanation:

charge, q = 10 C

time, t = 2 micro second

Current, i = q / t

i = 10 / (2 x 10^-6) = 5 x 10^6 A

(a)

distance, d = 1 m

the formula for the magnetic field is given by

B = \frac{\mu_{0}}{4\pi}\frac{2i}{d}

B = 10^{-7}\frac{2\times 5\times 10^{6}}{1}

B = 1 Tesla

Now the distance is d' = 1 km = 1000 m

B' = \frac{\mu_{0}}{4\pi}\frac{2i}{d}

B' = 10^{-7}\frac{2\times 5\times 10^{6}}{1000}

B' = 0.001 Tesla

(b) The magnetic field of earth is Bo = 3 x 10^-5 tesla

B / Bo = 3.3 x 10^4

B'/Bo = 33.3

4 0
3 years ago
. A weather balloon is inflated to a volume of 2.2 x 103 L with 37.4 g of helium. What is the density of helium in grams per lit
Margarita [4]
That is the mst best eway to find its solution.
37.4/2.2*10^3 =  0.017 gm/liter or  1.7*10^-2
so we conclude that option b is sorrect
6 0
3 years ago
What human activity uses the most water worldwide
Ronch [10]

Answer:

agriculture

Explanation:

7 0
3 years ago
Read 2 more answers
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