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3 years ago

Why is current a scalar quantity?

1 answer:

Nutka1998 [239]3 years ago

5 0

Despite current has a magnitude and a direction, like vectors, it is a scalar because it doesn't obey laws of vector addition. For instance, if we consider a junction of $90^{\circ}$ in a circuit, and two currents entering this junction, we know that the resultant current is just the algebraic sum of the two currents, not the vector sum, so it is not a vector quantity.

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A 53.3 kg woman slides down a 35.0° hill with an acceleration of 4.10 m/s. What is the friction force acting on the woman?

lorasvet [3.4K]

Answer:

I attached an image that should help.

Explanation:

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3 years ago

A speaker vibrates at a frequency of 200 Hz. What is its period

Daniel [21]

Period, T = 1/ f.
f = frequency = 200 Hz.

Period T = 1/200 = 0.005 seconds.

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3 years ago

Plain electromagnetic wave (in air) has a frequency of 1 MHz and its B-field amplitude is 9 nT a. What is the wavelength in air?

Norma-Jean [14]

Answer:

Part a)

$\lambda = 300 m$

Part b)

$E = 2.7 N/C$

Part c)

$I = 9.68 \times 10^{-3} W/m^2$

$P = 3.22 \times 10^{-11} N/m^2$

Explanation:

Part a)

As we know that frequency = 1 MHz

speed of electromagnetic wave is same as speed of light

So the wavelength is given as

$\lambda = \frac{c}{f}$

$\lambda = \frac{3\times 10^8}{1\times 10^6}$

$\lambda = 300 m$

Part b)

As we know the relation between electric field and magnetic field

$E = Bc$

$E = (9 \times 10^{-9})(3\times 10^8)$

$E = 2.7 N/C$

Part c)

Intensity of wave is given as

$I = \frac{1}{2}\epsilon_0E^2c$

$I = \frac{1}{2}(8.85 \times 10^{-12})(2.7)^2(3\times 10^8)$

$I = 9.68 \times 10^{-3} W/m^2$

Pressure is defined as ratio of intensity and speed

$P = \frac{I}{c} = \frac{9.68\times 10^{-3}}{3\times 10^8}$

$P = 3.22 \times 10^{-11} N/m^2$

6 0

3 years ago

Resultant vector of a force gives us information regarding ___________ of resultant force.

qaws [65]

Answer: direction

Explanation:

Given

The resultant vector of a force gives us information regarding the direction of the resultant force.

If there are multiple forces acted in a different direction then, the resultant vector describes the direction of the resultant force.

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3 years ago

The two properties of an electron that cannot be known exactly at the same time are the ____________________.

enyata [817]

Position and momentum.

This is Heisenberg's Uncertainty Principle:
Δx Δp ≥ h ÷ 4π, where Δx is the change in position, Δp is the change in momentum, and h is Planck's Constant.

6 0

3 years ago