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2 years ago

Which radioactive isotope would take the least amount of time to become stable? rubidium-91 iodine-131 cesium-135 uranium-238

2 answers:

8 0

The radioactive isotope that would take the least amount of time to become stable is rubidium-91. This is because this isotope is the most stable compared to the rest. This was determined by subtracting its atomic mass by its atomic number. The isotope with the least number of difference is the most stable, while the one with the greatest difference is the most unstable.

Difference:
Rubidium: 54 (most stable)
Iodine: 78
Cesium: 80
Uranium: 146 (least stable)

Darina [25.2K]2 years ago

5 0

Answer:

Explanation:

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Current X is 2.5 A and runs for 39 seconds. Current Y is 3.8 A and runs for 24 seconds. Which current delivered more charge, and

Aleonysh [2.5K]

Answer: B. Current x delivered 6.3 C more then Y

Explanation:

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2 years ago

The object distance for a concave lens is 8.0 cm, and the image distance is 12.0 cm. The height of the object is 4.0 cm. What is

swat32

The answer for this question, If I am correct, should be answer "D".

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2 years ago

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An x-ray tube is an evacuated glass tube that produces electrons at one end and then accelerates them to very high speeds by the

laila [671]

Answer:

a) V = 1.866 10² V , b) V = 3.424 10⁵ V , c) v = 8.1 10⁶ m / s

Explanation:

a) the potential difference is requested to accelerate the electrons up to 2.7% of the speed of light

v = 0.027 c

v = 0.027 3 10⁸

v = 8.1 10⁶ m / s

for this part we can use the conservation of mechanical energy

starting point. When electrons are at rest

Em₀ = U = q V

final point. Electrons with maximum speed

Em_f = K = ½ m v2

Em₀ = Em_{f}

e V = ½ m v²

V = ½ m v² / e

let's calculate

V = ½ 9.1 10⁻³¹ (8.1 10⁶)² / 1.6 10⁻¹⁹

V = 1.866 10² V

V = 1866 V

b) if this acceleration protons is the mass of the proton is m_{p} = 1.67 10-27

V = ½ 1.67 10⁻²⁷ (8.1 10⁶)² / 1.6 10⁻¹⁹

V = 3.424 10⁵ V

V = 342402 V

c) this potential difference should give the protons the same speed as the electrons

v = 8.1 10⁶ m / s

5 0

2 years ago

An electron is moving northward in a magnetic field. The magnetic force on the electron is toward the northeast. What is the dir

ira [324]

To solve this problem we will use the vector concept given by the cross product between two perpendicular vectors and which results in a vector perpendicular to these two. From the definition of the Magnetic Force we have to

$\vec{F}=q(\vec{v}\times\vec{B})$

From the property of cross product the magnetic force should point in the direction perpendicular to the plane containing the vectors v and B.

The direction of velocity is north, and the direction of the magnetic force is northeast.

This cannot be the case, as the direction of magnetic force is not perpendicular to the direction of velocity of the charge.

Therefore the correct option for the direction of the magnetic field is <em>"This situation cannot exist because of the relative orientations of the velocity and force vectors" </em>

7 0

1 year ago

At its lowest setting a centrifuge rotates with an angular speed of ω1 = 250 rad/s. When it is switched to the next higher setti

dalvyx [7]

Answer:

Part(a): The angular acceleration is $5.63~rad~s^{-2}$ .

Part(b): The angular displacement is $2629~rad$ .

Explanation:

Part(a):

If $\omega_{1},~\omega_{2}~and~\alpha$ be the initial angular speed, final angular speed and angular acceleration of the centrifuge respectively, then from rotational kinematic equation, we can write

$\alpha = \dfrac{\omega_{2} - \omega_{1}}{t}......................................................(I)$

where ' $t$ ' is the time taken by the centrifuge to increase its angular speed.

Given, $\omega_{i} = 250~rad~s^{-1}$ , $\omega_{f} = 750~rad~s^{-1}$ and $t = 9.5~s$ . From equation ( $I$ ), the angular acceleration is given by

$\alpha = \dfrac{750 - 250}{9.5}~rad~s^{-2} = 5.63~rad~s^{-2}$

Part(b):

Also the angular displacement ( $\Delta \theta$ ) can be written as

$&&\Delta \theta = \omega_{1}~t + \dfrac{1}{2}\alpha~t^{2}\\&or,& \Delta \theta = (250 \times 9.5 + \dfrac{1}{2} \times 5.63 \times 9.5^{2})~rad = 2629~rad$

8 0

1 year ago