Question of solved question

# Question When thermal neutrons (negligible kinetic energy) are used to induce the reaction ; α - particles are emitted with an energy of 1.83 MeV. Given the masses of boron neutron and as 10.01167, 1.00894 and 4.00386 u respectively. What is the mass of ? Assume that particles are free to move after the collision.

State two uses of a convex mirror

Solution:

Explanation:

The convex mirror reflects the light outwards and is therefore it is used to spread the light.

The two uses of convex mirror.

It is used as a rear view mirror in the vehicles.

It is used in the street light reflectors.

It is used as a sunglass.

The convex mirror is used as vehicles mirror,magnifying glasses.

Name three bad conductors of heat

Solution:

Explanation:

The object is bad conductors of heat means it is not conducted the heat easily.

The bad conductor heats are Plastic,rubber,wood.

The bad conductors of heat are plastic,rubber,wood,glass.

What is the force between two small charged spheres having charges

of 2×10^-7C and 3× 10^-7 C placed 30 cm apart in air?

Solution:

Explanation:

Charge on the first sphere, q1=2×10-7C

Charge on the second sphere, q2=3×10-7C

Distance between the spheres, r=30 cm=0.3m

Hence, force between the two small charged spheres is 6×10-3N .

The charges are of same nature. Hence, force between them will be repulsive

The ground state energy of hydrogen atom

is -13.6 eV. What are the kinetic and
potential energies of the electron in this state?
Ground state energy of hydrogen atom, E = - 13.6 eV
This is the total energy of a hydrogen atom. Kinetic energy is equal to the negative of
the total energy.
Kinetic energy = - E= - (- 13.6) = 13.6 eV
Potential energy is equal to the negative of two times of kinetic energy.
Potential energy = - 2 x (13.6) = - 27.2 eV

Solution:

Explanation:

Ground state energy of hydrogen atom is E=−13.67eV

The kinetic energy of the electron is given as: KE=−E =+13.67eV

The potential energy of the electron is given as: PE=−2×KE =−27.2eV

Hence,

The kinetic energy of the electron is +13.67eV

The potential energy of the electron is −27.2eV

The following configuration of gate equivalent to

A: NAND

B: XOR

C: OR

D: None of these

Solution:

Explanation:

The given output can be written as

Y=(A+B)(¯A+¯B)

Y=AA+A¯B+A¯B +B¯B

Y=0+A¯B+A¯B +0

Y=A¯B+A¯B

This the output of XOR gate.