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Novay_Z [31]
3 years ago
13

The SAME amount of current I passes through three different resistors. R2 has twice the cross-sectional area and the same length

as R1, and R3 is three times as long as R1 but has the same cross-sectional area as R1. 1)In which case is the CURRENT DENSITY through the resistor the smallest
Physics
1 answer:
Snezhnost [94]3 years ago
5 0

Answer:

resistor R₂ has the lowest current density

Explanation:

The current density is

          j = I / A

now let's analyze each case

a) R₂ has an area 2A₀ and a length L₀ that R₁

b) R₃ has an area Ao and a length 3L₀ what R₁

we can see that all the area is given in relation to the resistance R₁

 

the current density in R₁ is

         j₁ = I / A₀

the current density in R₂

         j₂ = I / 2A₀

         j₂ 2 = ½ I/A₀

the current density in R₃

         j₃ = I / A₀

         j₂ < j₁ = j₃

therefore resistor R₂ has the lowest current density

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If an object moves twice as fast how do you think its energy changes? halves
il63 [147K]

Answer:

If an object moves twice as fast its kinetic energy quadruples.

Explanation:

The kinetic energy (K₁) of a body of mass (m) that moves with speed (v) is:

K₁= 1/2 * m* v²

If we double the speed of the body, its kinetic energy (K₂) will be:

K₂= 1/2 * m*( 2v)²

K₂= 1/2 * m* 4 *v²

K₂= 4(1/2 * m *v²)

K₂= 4*K₁

6 0
3 years ago
A hydrogen atom that has an electron in the n = 2 state absorbs a photon. What wavelength must the photon possess to send the el
Deffense [45]

Answer:

486nm

Explanation:

in order for an electron to transit from one level to another, the wavelength emitted is given by Rydberg Equation which states that

\frac{1}{wavelength}=R.[\frac{1}{n_{f}^{2} } -\frac{1}{n_{i}^{2} }] \\n_{f}=2\\n_{i}=4\\R=Rydberg constant =1.097*10^{7}m^{-1}\\subtitiute \\\frac{1}{wavelength}=1.097*10^{7}[\frac{1}{2^{2} } -\frac{1}{4^{2}}]\\\frac{1}{wavelength}= 1.097*10^{7}*0.1875\\\frac{1}{wavelength}= 2.06*10^{6}\\wavelength=4.86*10{-7}m\\wavelength= 486nm\\

Hence the photon must possess a wavelength of 486nm in order to send the electron to the n=4 state

4 0
3 years ago
If a stone is dropped from a height of 400 feet, its height after t seconds is given by s = 400 − 16t2. Find its instantaneous v
soldier1979 [14.2K]

Answer:

v = -32 t

Explanation:

given,

s = 400- 16 t²

we know,

Velocity of an object is defined as the change in displacement per unit change in time.

velocity an also be return as

v = \dfrac{ds}{dt}

v = \dfrac{d}{dt}(400-16t^2)

v= 0 -2\times 16 t

v = -32 t

Hence, instantaneous velocity function given by v = -32 t

To calculate instantaneous velocity, you need to insert value of time.

ex, instantaneous velocity at t = 4 s

       v = -32 x 4 = -128 m/s.

5 0
3 years ago
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zubka84 [21]
The solution for this problem is computed by through this formula, F = kQq / d²Plugging in the given values above, we can now compute for the answer.
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4 0
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