Q.

Two independent harmonic oscillators of equal mass are oscillating about the origin with angular frequencies ω1 and ω2 and have total energies E1 and E2, respectively. The variations of their momenta p with positions x are shown in the figures. If ab=n2 and aR=n, then the correct equation(s) is(are)              [2015]

1 E1ω1=E2ω2  
2 ω2ω1=n2  
3 ω1ω2=n2  
4 E1ω1=E2ω2  

Ans.

(2, 4)

 For first harmonic oscillator,

Mass=m

Angular frequency=ω1

Amplitude=a

Total energy=E1

Maximum momentum, pmax=b

E1=12mω12a2                    ...(i)

pmax=mvmax=maω1b=maω1

ab=1mω1                          ...(ii)

For second harmonic oscillator,

Mass=m

Angular frequency=ω2

Amplitude=R

Maximum momentum, pmax=R

Total energy=E2

E2=12mω22R2                   ...(iii)

pmax=mvmax=mω2R

R=mω2Rmω2=1         ...(iv)

From eqns. (ii) and (iv),

ab=ω2ω1                                 ...(v)

From eqns. (i) and (iii),

E1E2=ω12a2ω22R2

If ab=n2 and aR=n then from eqn. (v),

ω2ω1=n2

and from eqn. (vi),

E1E2=ω12ω22×n2=ω1ω2

  E1ω1=E2ω2