Alfred Wegener first presented his hypothesis to the German Geological Society on 6 January 1912. His hypothesis was that the continents had once formed a single landmass, called Pangaea, before breaking apart and drifting to their present locations.
Answer:
7.8 mm
Explanation:
Wavelength = λ = 710 nm = 710×10⁻⁹ m
Distance between light sources = L = 9 m
Diameter of pinhole = d = 1 mm = 1×10⁻³ m
Rayleigh Criterion

Distance between difraction pattern is 7.8 mm.
Answer:
cal
Explanation:
= mass of ice = 100 g = 0.1 kg
= specific heat of ice = 0.5 cal/(kg°C)
= specific heat of water = 1 cal/(kg°C)
= Latent heat of fusion of ice = 80 J/g
= initial temperature of ice = - 20 °C
= final temperature of ice = 50 °C
Q = Heat gained
Heat gained is given as


cal
Answer:
Energy needed = 54.02 J
Explanation:
the Energy in an elastic spring from hookes law is given as
F= ke , therefore the energy (E) is
E = 
K = 19.5 N/cm
e = 1.39cm
E =
x 19.5 x 1.39
E = 13.55 J
The energy to stretch the spring for 6.93cm is
E =
x 19.5 x 6.93
E = 67.57 J
The more energy needed for the further stretch is
67.57 - 13.55
Energy needed = 54.02 J