11.9 RAY OPTICS 01- How to find the distance of image for convex mirror.

An object is placed at a distance of 6 cm from a convex mirror. If the focal length of a mirror is 12 cm find the position and nature of an image.

How to find angular acceleration - 02

The angular displacement of a particle is given by

𝜃= 〖5𝑡〗^3+〖10𝑡〗^2−2𝑡+3, where time ‘t’ is in second and 𝜃 is in rad. The angular acceleration of particle at

t = 3 sec

a) 90 𝑟𝑎𝑑 𝑠^(−2)                     b) 110 𝑟𝑎𝑑 𝑠^(−2) 

c) 100 𝑟𝑎𝑑 𝑠^(−2)                   d) 120 𝑟𝑎𝑑 𝑠^(−2)

How to find angular acceleration....

The angular displacement of a particle is given by

𝜃= 〖6𝑡〗^2−4𝑡+6, where time ‘t’ is in second and 𝜃 is in rad. The angular acceleration of particle at t = 4 sec

a) 6 𝑟𝑎𝑑 𝑠^(−2)                       b) 24 𝑟𝑎𝑑 𝑠^(−2) 

c) 12 𝑟𝑎𝑑 𝑠^(−2)                     d) 48 𝑟𝑎𝑑 𝑠^(−2)

The relation between time ‘t’ and distance ‘x’ is t=ax^2+bx

The relation between time ‘t’ and distance ‘x’ is t=ax^2+bx,   where ‘a’ and  ‘b’ are constant. The acceleration is…..

a.   -2abv^2         
b.     2bv^2           
c.   -2av^3             
d.    2av^2

Coefficient of static friction between coin and the turntable.

A coin is kept at a distance 10 cm from the center of turn table of radius 1 m just begin to slip, when the turn table rotate at a speed of 90 r.p.m. calculate the coefficient of static friction between the coin ant turn table.

Solution:

JEE MAINS 2013 Measurement

Let [ε_o] denote the dimensional formula of the permittivity of vacuum. If M = mass, L = length and T = time and A = electric current then,

Top of Form

(A) [ ε_o ] = [ M⁻¹ L⁻³ T⁴ A² ]                          

(B) [ ε _o] = [ M⁻¹ L² T⁻¹ A⁻² ]

(C) [ ε_o ] = [ M⁻¹ L² T⁻¹ A ]

(D) [ ε_o ] = [ M⁻¹ L⁻³ T² A ]

The two charges of magnitude 1 μC and 2 μC are separated by 10 cm from each other. At what point on the line joining the two charges is the electric field strength is zero.

Solution: