It is an example of reflection of wave. C.
Answer:
2.16×10⁻⁶ N
Explanation:
Applying,
F = kqq'/r² (coulomb's Law)....................... Equation 1
Where F = electrostatic force, k = coulomb's constant, q = charge on the styrofoam, q' = charge on the grain of salt, r = distance between the charges.
From the question,
Given: q = 0.002 mC = 2.0×10⁻⁶ C, q' = 0.03 nC = 3.0×10⁻¹¹ C, r = 0.5 m
Constant: k = 8.99×10⁹ Nm²/C²
Substitute these values into equation 1
F = (2.0×10⁻⁶)(3.0×10⁻¹¹)(8.99×10⁹)/0.5²
F = 2.16×10⁻⁶ N
Answer:
Q = c M ΔT where c is the heat capacity and M the mass present
Q2 / Q1 = M2 / M1 since the other factors are the same
M = ρ V where ρ is the density
M = ρ Π (d / 2)^2 where d is the diameter of the sphere
M2 / M1 = (2 D/2)^2 / (D/2)^2 = 4
It will take 4Q heat to heat the second sphere
Answer:
Elliptical galaxies
Explanation:
Edwin Hubble classified galaxies into three categories
Elliptical
Spiral
Lenticular
The elliptical galaxies have an elipsoidal shape roughly. They have stars which are old and the primary light source of the galaxy. The formation of new stars is very limited. This increases the brightness of the galaxy. The mass of the stars are low. So, far the percentage elliptical galaxies is low compared to other galaxies.
