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3 years ago

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Why are some atoms radioactive

1 answer:

Dmitry_Shevchenko [17]3 years ago

8 0

Atoms<span> are made of three types of sub-atomic particle: neutrons and protons in the nucleus and electrons orbiting the nucleus. </span>Some<span> materials are </span>radioactive<span> because the nucleus of each </span>atom<span> is unstable and gives out nuclear radiation in the form of alpha particles, beta particles or gamma rays.</span>

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Newton's 1st law of motion States that

ivann1987 [24]

Answer:

B is right at first I thought I was wrong

Explanation:

Newton's first law states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force. This tendency to resist changes in a state of motion is inertia.

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2 years ago

2. Four resistors of 2 ohm each are connected first in series and then in parallel with a battery.Find the ratio of electric cur

Serjik [45]

Answer:

Ratio of series current to parallel

= 1 : 8

Explanation:

Total resistance Rt

For series, Rt = 2+2+2+2 = 4ohms

For parallel, 1/Rt = 1/2 + 1/2 + 1/2 + 1/2

1/Rt = 4/2, Rt = 2/4 ohms.

If we use a 1V battery, then,

I = V/Rt

I = 1/4 = 0.25 ampere for series arrangement.

I = 1/0.5 = 2 ohms.

Ratio of current of series to parallel = 0.25 : 2

= 1 : 8

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3 years ago

Read 2 more answers

The time, t, required to drive a fixed distance varies inversely as the speed, r. It takes 3 hr at a speed of 14 km/h to driv

kenny6666 [7]

Answer:

time taken with speed 23 km/h will be 1.8 hours or 1 hour 48 minutes

Explanation:

Given:

Time is inversely proportional to the speed

mathematically,

t ∝ (1/r)

let the proportionality constant be 'k'

thus,

t = k/r

therefore, for case 1

time = 3 hr

speed = 14 km/hr

3 = k/14

also,

for case 2

let the time be = t

r = 23 km/h

thus,

we have

t = k/23

on dividing equation 2 by 1

we get

$\frac{t}{3}=\frac{k/23}{k/14}$

or

$t=\frac{14\times3}{23}$

or

t = 1.8 hr = or 1 hour 48 minutes ( 0.8 hours × 60 minutes/hour = 48 minutes)

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3 years ago

A 6.89-nC charge is located 1.76 m from a 4.10-nC point charge. (a) Find the magnitude of the electrostatic force that one charg

iogann1982 [59]

Answer: a) 8.2 * 10^-8 N or 82 nN and b) is repulsive

Explanation: To solve this problem we have to use the Coulomb force for two point charged, it is given by:

$F=\frac{k*q1*q2}{d^{2}}$

Replacing the dat we obtain F=82 nN.

The force is repulsive because the points charged have the same sign.

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3 years ago

Each of two small non-conducting spheres is charged positively, the combined charge being 40 μC. When the two spheres are 50 cm

Phantasy [73]

Answer:

1.44 x 10⁻⁶ C

Explanation:

$q_{1}$ = charge on one sphere

$q_{2}$ = charge on other sphere

$q$ = Total charge on the two spheres = 40 μC

$q_{1}+ q_{2}$ = $q$

$q_{1}+ q_{2}$ = 40 x 10⁻⁶

$q_{1}$ = (40 x 10⁻⁶) - $q_{2}$ eq-1

$r$ = distance between the two spheres = 50 cm = 0.50 m

$F$ = magnitude of force between the two spheres = 2.0 N

Magnitude of force between the two spheres is given as

$F = \frac{k q_{1} q_{2}}{r^{2}}$

$2.0 = \frac{(9\times 10^{9}) ((40\times 10^{-6}) - q_{2}) q_{2}}{0.50^{2}}$

$q_{2}$ = 1.44 x 10⁻⁶ C

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3 years ago