CBSE 11TH PHYSICS - Online Test

Answer : Option B
Explaination / Solution:

Kinetic  energy of rotation 

K =12Iω2

n=60060=10 revolution per second

angular velocity ω=2πn=2π×10=20π rad/sec

moment of inertia about an axis passing through centre of solid sphere

I=25MR2

Kinetic  energy of rotation 

K=12Iω2=12×25MR2×(20π)2=80π2MR2

Answer : Option B
Explaination / Solution:

The force of viscosity on a small sphere moving through a viscous fluid is given by:
Fd=6πηRv

Where:

• Fd is the frictional force – known as Stokes' drag – acting on the interface between the fluid and the particle
• η is the dynamic viscosity 
• R is the radius of the spherical object
• v is the flow velocity relative to the object.

In SI units, Fd is given in Newtons, η in Pa·s, R in meters, and v in m/s.

Answer : Option A
Explaination / Solution:

PV=nRT

Answer : Option D
Explaination / Solution:

Heat transfer through radiation takes place in form of electromagnetic waves.

Answer : Option C
Explaination / Solution:

Principle of homogenity of dimensions states that “For an equation to be dimansionally correct, the dimensions of each term on LHS must be equal to the dimensions of each term on RHS.”

Answer : Option B
Explaination / Solution:

The time period of the SHM is given by T=2πmk−−√ where 'm' be the mass of the body (constant) , 'k' restoring force constant as T depends on 'm' and 'k' and they are constant for the system, so the corresponding Time period of the motion is Constant.

Answer : Option B
Explaination / Solution:

A polar orbiting satellite closely parallels the earth's meridian lines. It passes over the north and south poles each revolution. As the earth rotates to the east beneath the satellite, each pass monitors an area to the west of the previous pass at intervals of roughly 90 to 100 minutes. These strips can be pieced together to produce a picture of a larger area.They are used in monitoring the weather, observing the Earth’s surface, military uses including spying.

Answer : Option A
Explaination / Solution:

Let's let west direction as +ve.

Initial velocity u = + 20.0 m/s

Final velocity = ?

Acceleration a = - 1.0 m/s​​​​​​2

Time taken t = 37.0 s

We know,

v = u + at

=> v=20.0−37.0×1

=> v = -17.0

-ve sign shows direction of velocity is opposite. So velocity is 17.0 m/s due east.

Answer : Option B
Explaination / Solution:
No Explaination.

Answer : Option A
Explaination / Solution:

Although vectors and scalars represent different types of physical quantities, it is sometimes necessary for them to interact. While adding a scalar to a vector is impossible because of their different dimensions in space, it is possible to multiply a vector by a scalar.