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4 years ago

What element is used as a source of radiation in smoke detectors?

Physics

1 answer:

mart [117]4 years ago

4 0

Americium ( A source of alpha radiation to detect and identify smoke.)

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Three deer, a, b, and c, are grazing in a field. deer b is located 62.1 m from deer a at an angle of 54.3 ° north of west. deer

sveticcg [70]

by cosine law we know that

$c^2 = a^2 + b^2 - 2 abcos\theta$

$\theta = 180 - 54.3 - 79.1 = 46.6 degree$

now using above equation

$93.8^2 = 62.1^2 + b^2 - 2*62.1*b * cos46.6$

$4942.03 = b^2 - 85.34 b$

$b^2 - 85.34b - 4942.03 = 0$

by solving above quadratic equation we have

$b = 124.9 m$

so it is at distance 124.9 m from deer a

4 0

3 years ago

A truck is moving at a constant speed of 50 m/s. A boy riding in the back of the truck throws a newspaper out the back of the tr

lbvjy [14]

Answer:

70m/s

Explanation:

7 0

4 years ago

Two objects of the same mass, but made of different materials, are initially at the same temperature. Equal amounts of heat are

adelina 88 [10]

Answer:

The final temperature of the two objects is the same.

Explanation:

The expression for the heat energy in terms of mass, specific heat and the change in the temperature is as follows:

$Q=mc(T_{f} -T_{i})$

Here, Q is the heat energy, m is the mass of the object, c is the specific heat and $T_{f},T_{i}$ are the final temperature and initial temperature.

According to the given question, Two objects of the same mass, but made of different materials, are initially at the same temperature. Equal amounts of heat are added to each object.

$Q=mc(T_{f}-T_{i})$ ............(1)

$Q=mc(T'_{f}-T_{i})$ .............(2)

From (1) and (2),

$mc(T_{f}-T_{i})=mc(T'_{f}-T_{i})$

$T_{f}-T_{i}=T'_{f}-T_{i}$

$T_{f}=T'_{f}$

Therefore, the final temperature of the two objects is the same.

6 0

3 years ago

Suppose a greenhouse is to be constructed to keep plants warm in the winter. Which material should be used for the windows of th

Anastasy [175]

Answer:

the answers, material D meets the requested characteristics

Explanation:

The objective of an insulating material for the house, must allow solar radiation to enter, so that the plants can perform photosynthesis and must prevent radiation from inside the house from being lost.

Therefore the material must meet two conditions be transparent to sunlight and be absorbed from the radiation coming from the house; this is to leave for visible light and absorb infrared radiation

Reviewing the answers, material D meets the requested characteristics

4 0

3 years ago

Why is the unit of velocity called derived unit ?

navik [9.2K]

Answer:

Explanation:

The general consensus is that it's more “natural” to define distance (meter) and time (second) and as base units, and derive velocity a the ratio between them. ... The general consensus is that it's more “natural” to define distance (meter) and time (second) and as base units, and derive velocity a the ratio between them.

6 0

3 years ago