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grin007 [14]
2 years ago
5

a person when asked to speak up,increases her sound level from 30dB to 60dB.The amount of power per unit area increased by? a)30

00 times b)30 times c)2 times d)1000 times
Physics
1 answer:
aivan3 [116]2 years ago
4 0

Answer:

d) 1000 times

Explanation:

As we know that difference of sound level is given as

L_2 - L_1 = 10 Log \frac{I_2}{I_1}

so here we need to find the ratio of two intensity

it is given as

Log\frac{I_2}{I_1} = \frac{(L_2- L_1)}{10}

Log\frac{I_2}{I_1} = \frac{60 - 30}{10}

Log\frac{I_2}{I_1} = 3

now we have

\frac{I_2}{I_1} = 10^3

so it is

d) 1000 times

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A single-turn square loop carries a current of 16 A . The loop is 15 cm on a side and has a mass of 3.8×10^−2kg . Initially the
DiKsa [7]

Answer:

The minimum magnetic field is 0.078 T.

Explanation:

Given that,

Current = 16 A

Side = 15 cm

Mass m= 3.8\times10^{-2}\ kg

Mass each segment in given square loop is

m=\dfrac{3.8\times10^{-2}}{4}

We need to calculate the torque due to gravity

Using formula of torque

\tau_{g}=2mg(\dfrac{L}{2})+mgL

\tau_{g}=2mgL

The torque due to magnetic field

\tau_{B}=FL

\tau_{B}=BIL^2

The equilibrium condition

\tau_{B}=\tau_{g}

Put the value into the formula

BIL^2=2mgL

B=\dfrac{2mgL}{IL^2}

B=\dfrac{2mg}{IL}

Put the value into the formula

B=\dfrac{2\times\dfrac{3.8\times10^{-2}}{4}\times9.8}{16\times15\times10^{-2}}

B=0.078\ T

Hence, The minimum magnetic field is 0.078 T.

7 0
3 years ago
A balloonist happens to drop his metal ballpoint pen from his balloon as he is taking notes on his flight. Because his pen has a
Lerok [7]
So this is dealing with the conservation of energy. So you set kinetic energy equal to potential energy, so it looks like this:

1/2mv^2=mgh. The m's cancel out, so it is 1/2v^2=gh.

To find out what the height h is, divide g on both sides, so...

h=0.5v^2/g. v=22m/s, g=9.81m/s^2, so h=(0.5)(22^2)/(9.81)=24.67m
5 0
3 years ago
Will the positioning of your Slinky along the east-west, north-south, or some other orientation affect your readings? Why?
Oxana [17]

Positioning your Slinky along any direction different from its initial position will affect your reading, because there will be change in the magnetic field.

<h3>Effect of magnet on Slinky</h3>

If the Slinky is made of an iron alloy, it can be magnetized by itself. Moving the Slinky around can cause a change in the magnetic field, even if no current is flowing.

When there is a change in the magnetic field, the reading changes.

At any point, you change the orientation of the Slinky, you will need to zero the reading or adjust the Slinky back to its initial position, even if the sensor does not move.

Thus, Positioning your Slinky along any direction that is different to its initial position will affect your reading because there will be change in the magnetic field.

Learn more about magnetic field here: brainly.com/question/7802337

5 0
2 years ago
Two cars leave towns 680 kilometers apart at the same time and travel toward each other. one car's rate is 10 kilometers per hou
Evgen [1.6K]

D = distance between the cars at the start of time = 680 km

v₁ = speed of one car

v₂ = speed of other car = v₁ - 10

t = time taken to meet = 4 h

distance traveled by one car in time "t" + distance traveled by other car in time "t" = D

v₁ t + v₂ t = D

(v₁ + v₂) t = D

inserting the values

(v₁ + v₁ - 10) (4) = 680

v₁ = 90 km/h

rate of slower car is given as

v₂ = v₁ - 10

v₂ = 90 - 10 = 80 km/h

5 0
3 years ago
Distinguish between friction force and motion?
Ksju [112]

Friction force is when you rub 2 things together and they get warm. Motion, on the other hand, is if your walking along the sidewalk - you hardly get warmer -------


Unless it's a colder day outside and you're walking SO you decide to rub your hands together to get warm, but if you were just walking , its motion and only motion - no friction :):)

6 0
3 years ago
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