That's right, the correct answer is
<span>A) The isotopes have a long half-life and only remain radioactive for a long time period
The half life of an isotope is the time it takes for the amount of the sample to reduce to half of its initial value. If an isotope has a long half-life, it means it takes a long time to reduce down to a significant level, so it will remain radioactive for a long time period.</span>
Answer:
the magnitude of the electron's acceleration a at that moment =
Explanation:
The expression for the magnetic field is :
where:
= permeability of free space =
I = current in the wire = 12.7 A
r = distance from the wire to the field point = 3.47 cm =
The magnetic force exerted in the electrond passing through the straight conducting wire is:
F = Bvgsinθ
where :
B = magnetic field =
v = speed of light = (30.5 % )
q = charge of electrons =
θ = angle between speed of electron & field = 90°
F = () × (30.5 % ) × () × ( sin 90°)
F =
From Newtons second Law ;
F = ma
where m = mass =
Thus, the magnitude of the electron's acceleration a at that moment =
Answer:
the electric potential at an infinite distance is the workdone in moving a charge from one point at an infinite distance to another point at an infinite distance. This will be zero.
Explanation:
Electric potential is given by
E= kQ/r²
If r becomes ∞, then
E= kQ/(∞)²= 0
So electric potential at an infinite distance away from the rod is zero
Answer:
67.8 m.
Explanation:
For 0.3 sec which is the response time , he will keep on moving with velocity
undiminished or at 26 m/s .
Distance travelled during this period
= 26 x .3 =7.8 m
For rest of the time ie during 4 - .3 = 3.7 s , he decelerates with deceleration of 5.3 ms⁻² and initial velocity of 26 m/s
s = u t - 1/2 a t²
s = 26 x 3.7 - .5 x 5.3 x 3.7 x 3.7
= 96.2 - 36.28
= 60 m approx.
Total distance travelled
=60 + 7.8 = 67.8 m.
Answer:
D. accelerated
Explanation:
According to Newton's first law of motion, an object always remains in its state of rest or in uniform motion until an external unbalanced force is acted upon the object. This means if an external unbalanced force is acted on the object, it will come to a non-uniform motion i.e., an accelerated motion.
Let me first get you clear that uniform motion is determined by a constant velocity and a state of rest is considered by a zero velocity or speed. But, here we have an unbalanced force acting on the object. This means the object will change its velocity and hence, it has an accelerated motion.