Other Physics Answers

The diagram shows what happens to each 100 joules of energy from the coal which is burned in a power station when the electricity is used for lighting.

the speed of a bullet can be estimated by firing it horizontally into a block of wood suspended from a long string so that the bullet becomes embedded in the centre of the block. the block swings so that the center of mass rises a vertical distance of 0.15 m. the mass of the bullet is 10g and that of the block is 1.99kg

i) assuming that air resistance can be neglected calculate the speed of the block and bullet immediately after the impact

ii) calculate the speed of the bullet before the impact

iii) if the tension in the string before the impact T give two reasons why the tension in the string immediately after the impact is greater than T

Calculate the Hall coefficient of sodium based on free electron model. Sodium has bcc structure and the side of the cube is 4.28 Å.

2.45 ×10−9 m3 C−1

3.28 ×10−9 m3 C−1

4.50 ×10−9 m3 C−1

1.65 ×10−9 m3 C−1

Silicon has a diamond structure with unit-cell-edge a=0.542 nm.The interatomic separation is:

0.122 nm

0.234 nm

0.383 nm

0.542 nm

A metal with body centered cubic (bcc) structure shows the first (i.e. smallest angle) diffraction peak at Bragg angle of θ=30∘. The wavelength of X-ray used is 2.1Å. The volume of primitive unit cell of the metal is :

26.2(Å3)

13.1(Å3)

9.3(Å3)

4.6(Å3)

A metal with body centered cubic (bcc) structure shows the first (i.e. smallest angle) diffraction peak at Bragg angle of θ=30∘. The wavelength of X-ray used is 2.1Å. The volume of primitive unit cell of the metal is :

26.2(Å3)

13.1(Å3)

9.3(Å3)

4.6(Å3)

What is the escape velocity at the surface of the sun?

What is the acceleration due to gravity above the surface of Earth at an altitude of 6.37×106 m?

Two bodies of the same mass are separated by a distance d. If their distance is increased by a factor of four then

the magnitude of the gravitational force, F, becomes