Application of surface tension:
1) A needle placed on water can be made to float due to the surface tension of water.
2) Mosquito eggs can float on water because of its surface tension.
3) Toothpaste contains soap, which reduce the surface tension and helps it spread freely in the mouth.
Answer : The energy released in first step of thorium-232 decay chain is 
Explanation :
First we have to calculate the mass defect 
.
The balanced reaction is,
Mass defect = Sum of mass of product - sum of mass of reactants
conversion used : 
Now we have to calculate the energy released.
The energy released is
Therefore, the energy released in first step of thorium-232 decay chain is
Answer:
r = 0.0414mm
F = 757,692.3Hertz
Explanation:
If the body enters space with uniform magnetic field B, the force experienced by the object is expressed as
F = qvBsintheta... 1
Also, if the body undergoes a circular motion, the force experienced by the body in a circular path is given as
Fc = mv²/r... 2
Equating both forces
F = Fc
qvBsin theta = mv²/r
Since the body enters perpendicular to the field, theta = 90°
The equality becomes;
qvB sin90° = mv²/r
qvB = mv²/r
qB = mv/r
r = mv/qB
Given mass of the electron m = 9.11×10^-31kg
Velocity of the object v = 197m/s
Charge on the electron q = 1.6×10^-19C
Magnetic field B = 2.71×10^-5T
Substituting this value into the equation to get the radius r we have;
r = 9.11×10^-31 × 197/1.6×10^-19 × 2.71×10^-5
r = 1794.67×19^-31/4.336×10^-24
r = 413.89×10^-7
r = 0.0000414m
r = 0.0414mm
b) Frequency of the motion F = w/2π where w is the angular velocity
Since w = v/r
F = (v/r)/2π
F = v/2πr
F = 197/2π(0.0000414)
F = 757,692.3Hertz
