Question of Exercise 2

Current Electricity of Class 12

Question

If I1, I2, I3 and I4 are the respective r.m.s. values of the time varying currents as shown in the four cases I, II, III and IV. Then identify the correct relations. 49 50 51 52

Answer

Option 1 I1 = I2 = I3 = I4

Option 2  I3 > I1 = I2 > I4

Option 3 I3 > I4 > I2 = I1

Option 4 I3 > I2 > I1 > I4

Frequently Asked Questions

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.

Final Answer:

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.

Final Answer: 

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

charged spheres

Final Answer:

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?
Answer
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

Final Answer:

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

configuration

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.

Final Answer:

The correct option is (B) ( XOR ) 

 

 

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