Physics Questions and Answers

The equation that establishes a relationship between the amount left undecayed, 

A, the initial amount, A0, and the number of half-lives that pass in a period of time t looks like this:

\(\frac{1}{2^n} * A_0  = A\)

\(\frac{1}{2^n} * 120 = 15\)

\(\frac{1}{2^n}\) = \(\frac{15}{120}\)

\(\frac{1}{2^n}\) = \(\frac{1}{8}\)

\(\frac{1}{2^n}\) = \(\frac{1}{2^3}\)

\(2^n = 2^3\) 

n = 3
:6days ÷ 3 = 2days

Distilled water is free of salts and is a poor conductor of electricity.

Lost voltage = I x R

= 4 x 0.55

= 2.2V

If the zinc used in the simple cell is of the impure commercial variety bubbles of hydrogen will be seen coming off the zinc. This is called local action

 volumetric expansion (γ) = 3x Linear expansion

S = ut + \(\frac{1}{2}\)at\(^2\)

40 = 0 x 10 + \(\frac{1}{2}\)a x 10\(^2\)

50a = 40

a = \(\frac{40}{50}\)

= 0.8m/s\(^2\)

Tire treads provide your tires the ability to grip the road safely enhancing proper traction.

Helps your vehicle to be able to accelerate smoothly and as well to be able to brake more quickly.

If both the coil and the magnet are stationary, then there is no change in the magnetic flux and hence no current is induced in the coil.

M → \(\frac{Hi}{Ho}\) = \(\frac{Di}{Do}\)

where M is the magnification, Hi is the height of the image, Ho is the height of the object, Di is the distance from the lens to the in-focus projected image, and Do is the distance from the object to the lens.

But Di = \(\frac{Hi * Do}{Ho}\) → \(\frac{20 * 30}{40}\)

Image distance(Di) = 15cm

The angular wave number k = \(\frac{2π}{λ}\) expresses the number of radians in a unit of distance.