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choli [55]
2 years ago
15

I have a voltage source of 12V but a light that only burns at 5V. The lamp works on 18 mA. Calculate the resistance that you EXT

RA have to include in this series connection.
Physics
1 answer:
Gala2k [10]2 years ago
5 0

Answer:

The resistance that will provide this potential drop is 388.89 ohms.

Explanation:

Given;

Voltage source, E = 12 V

Voltage rating of the lamp, V = 5 V

Current through the lamp, I = 18 mA

Extra voltage or potential drop = 12 V - 5 V = 7 V

The resistance that will provide this potential drop (7 V) is calculated as follows:

R = \frac{V}{I} = \frac{7 \ V}{18 \times 10^{-3} A} \ = 388.89 \ ohms

Therefore, the resistance that will provide this potential drop is 388.89 ohms.

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Mike rides his horse with a constant speed of 20 km/h. How far can he travel in 4 hours?
gizmo_the_mogwai [7]

Answer:

Mike can travel 80 Km in 4 hours

4 0
2 years ago
If the coefficient of kinetic friction between tires and dry pavement is 0.84, what is the shortest distance in which you can st
liberstina [14]

Answer:

The shortest distance in which you can stop the automobile by locking the brakes is 53.64 m

Explanation:

Given;

coefficient of kinetic friction, μ = 0.84

speed of the automobile, u = 29.0 m/s

To determine the  the shortest distance in which you can stop an automobile by locking the brakes, we apply the following equation;

v² = u² + 2ax

where;

v is the final velocity

u is the initial velocity

a is the acceleration

x is the shortest distance

First we determine a;

From Newton's second law of motion

∑F = ma

F is the kinetic friction that opposes the motion of the car

-Fk = ma

but, -Fk = -μN

-μN = ma

-μmg = ma

-μg = a

- 0.8 x 9.8 = a

-7.84 m/s² = a

Now, substitute in the value of a in the equation above

v² = u² + 2ax

when the automobile stops, the final velocity, v = 0

0 = 29² + 2(-7.84)x

0 = 841 - 15.68x

15.68x = 841

x = 841 / 15.68

x = 53.64 m

Thus, the shortest distance in which you can stop the automobile by locking the brakes is 53.64 m

4 0
2 years ago
1600 AM broadcasts radio waves with wavelengths<br> of about 187.37 m. Convert this to miles.
nikklg [1K]

Answer:

The wavelength in miles is <u>0.1165 miles</u>.

Explanation:

Given:

Wavelength of the radio wave is 187.37 m.

Now, the wavelength is given in meters.

We need to convert the wavelength from meters to miles.

In order to convert meters to miles, we have to use their conversion factor.

We know that,

1 meter = \frac{1}{1609}\ miles

Therefore, the conversion factor is given as:

CF=\frac{1}{1609}\ miles\ per\ meter

So, the wavelength in miles is given as:

Wavelength=\textrm{Wavelength in meters}\times CF\\\\Wavelength=187.37\ m\times \frac{\frac{1}{1609}\ miles}{1\ m}\\\\Wavelength=\frac{187.37}{1609}\ miles\\\\Wavelength=0.1165\ miles

Hence, the wavelength in miles is 0.1165 miles.

7 0
3 years ago
A circular coil of radius r = 5 cm and resistance R = 0.2 is placed in a uniform magnetic field perpendicular to the plane of th
Yuri [45]

Answer:

the question is incomplete, the complete question is

"A circular coil of radius r = 5 cm and resistance R = 0.2 ? is placed in a uniform magnetic field perpendicular to the plane of the coil. The magnitude of the field changes with time according to B = 0.5 e^-t T. What is the magnitude of the current induced in the coil at the time t = 2 s?"

2.6mA

Explanation:

we need to determine the emf induced in the coil and y applying ohm's law we determine the current induced.

using the formula be low,

E=-\frac{d}{dt}(BACOS\alpha )\\

where B is the magnitude of the field and A is the area of the circular coil.

First, let determine the area using \pi r^{2} \\ where r is the radius of 5cm or 0.05m

A=\pi *(0.05)^{2}\\ A=0.00785m^{2}\\

since we no that the angle is at 0^{0}

we determine the magnitude of the magnetic filed

B=0.5e^{-t} \\t=2s

E=-(0.5e^{-2} * 0.00785)

E=-0.000532v\\

the Magnitude of the voltage is 0.000532V

Next we determine the current using ohm's law

V=IR\\R=0.2\\I=\frac{0.000532}{0.2} \\I=0.0026A

I=2.6mA

6 0
3 years ago
What us the difference between accurate data and reproducible data
Nikolay [14]

It's just in the name! Accurate data is helpful, and correct, but reproducible data is all of that, and is able to be given to other people through different sources! At least, that's what my understanding of them are. Hope it helps!

4 0
3 years ago
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