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Luda [366]
3 years ago
14

Which optical device can focus light to a point through reflection?

Physics
1 answer:
nekit [7.7K]3 years ago
6 0

Answer:

It is A

Explanation:

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A sample of radium-226 will decay to ¼ of its original amount after 3200 years. What is the half-life of radium-226?
lesantik [10]
<h3><u>Answer</u>;</h3>

1600 years

<h3><u>Explanation</u>;</h3>
  • Half life is the time taken for a radioactive isotope to decay by half of its original amount.
  • We can use the formula; N = O × (1/2)^n ; where N is the new mass, O is the original amount and n is the number of half lives.
  • A sample of radium-226 takes 3200 years to decay to 1/4 of its original amount.

Therefore;

<em>1/4 = 1 × (1/2)^n</em>

<em>1/4 = (1/2)^n </em>

<em>n = 2 </em>

Thus; <em>3200 years is equivalent to 2 half lives.</em>

<em>Hence, the half life of radium-226 is 1600 years</em>

3 0
3 years ago
A planet has a circular orbit around a star. It is a distance of 53,000,000 km from the centre of the star.
Kipish [7]

Answer:

it takes 365 days to revolve around the star(sun)

5 0
3 years ago
Some expressways are curved, banked and designed to maximize ___________ at higher speeds.
Liono4ka [1.6K]

Answer:

Safety

Explanation:

Expressways are banked to resist centifugal action

6 0
3 years ago
An undersea research chamber is spherical with an external diameter of 5.50 m . The mass of the chamber, when occupied, is 87600
dmitriy555 [2]

Answer:

the buoyant force on the chamber is F = 7000460 N

Explanation:

the buoyant force on the chamber is equal to the weight of the displaced volume of sea water due to the presence of the chamber.

Since the chamber is completely covered by water, it displaces a volume equal to its spherical volume

mass of water displaced = density of seawater * volume displaced

m= d * V , V = 4/3π* Rext³

the buoyant force is the weight of this volume of seawater

F = m * g = d * 4/3π* Rext³ * g

replacing values

F = 1025 kg/m³ * 4/3π * (5.5m)³ * 9.8m/s² = 7000460 N

Note:

when occupied the tension force on the cable is

T = F buoyant - F weight of chamber  = 7000460 N - 87600 kg*9.8 m/s² = 6141980 N

4 0
3 years ago
Two point charges are arranged in a line with point P, which is on the right. The
MAVERICK [17]

Answer:

chicken

Explanation:

you like chicken and want to eat it

6 0
2 years ago
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