JEE Class main Answered

Qn. # 1

Gravitational force is weakest force and Nuclear force is strongest force in nature.

Hence the correct order is   F_g < F_e < F_n

--------------------------------------------------

Qn. # 2.

1 degree = ( π / 180 ) rad

1 degree = 60 minute = 3600 second

1 arc second = 1/3600 degree

1 arc second = (1/3600) × ( π / 180 ) rad

hence correct answer is  (c)  

-------------------------------------------------------------

Qn # 3

Let a quantity x is expressed in terms of a, b, c and d as follows

..........................(1)

If a quantity α is n power of another quantity  β , then

then relative error in α is

If a quantity p is either a product of two quantities q and r or division of q by r , then the relative error in a is

using these concepts , relative error in x as given by eqn.(1) is

( percentage error = relative error × 100 )

Hence percentage error in x is 34%

------------------------------------------------------------------

Qn #4

Momentum P = mass × velocity

Dimension of momentum P = M L T^-1

If momentum is expressed as , p = c t + d t² , where c and d are constant and t is time.

Dimension of c is  M L T^-2  and dimension of d is M L T^-3

----------------------------------------------------

Qn # 5

Slope of Position-time graph is

slope = ( change of position ) / ( change of time ) =  ΔS / Δt = instantaneous velocity