As a head-up, it is important to notice that a white dwarf only shines thanks to the stored energy and light, because a white dwarf doesn't have any hydrogen left to perform nuclear fusion.
Now the process:
First, the white dwarf accumulates all the extracted matter from its companion, onto its own surface. This extra matter increases the white dwarf's temperature and density.
After a while, the star reaches about 10 million K, so nuclear fusion can begin. The hydrogen that has been "stolen" from the other star and accumulated in the white dwarf's surface it's used for the fusion, dramatically increasing the star's brightness for a short time, causing what we know as a Nova.
As this fuel its quickly burnt out or blown into space, the star goes back to its natural white dwarf state. Since the white dwarf nor the companion star are destroyed in this process, it can happen countless of times during their lifespan.
The answer is C.
Ionic compounds are those that bring together anions and cations bonded together by ionic bonds. The electrostatic forces of the different charges are significant in the bonds that make them strong hence require high energy to break them (high melting point). Due to the regular structure of ionic compound that tend to form lattices in solid form, when struck, they shatter along the lines of weakness of the lattice.
Answer:
55000000 years
Explanation:
Rate of North American Plate moving (Velocity) = 20 mm/yr
Degrees New York has to move = 10° west
New York's longitude = 110 km/°
Distance of New York = 110×10 = 1100 km
= 1100×10⁶ mm
∴ Time taken by New York to move 10° west is 55000000 years
Answer:
Explanation:
Given
Four Point charges are Placed at the corner of a square with side length a
Length of diagonal 
Distance of charge from center 
Potential at the center due to four charges is given by
as all the four charges are equal and placed symmetrical about center
Work done required to bring a fifth charge q from infinity to the center of the square
