Most Important Selected Qs for JEE AdvancedPhysicsLaws of Motion
A disc of radius a and mass m rests between two light rods, which are smoothly hinged together at point O with their ends A and B resting on a smooth table and are maintained in equilibrium by string AB as shown in the figure. Choose the correct option (s).
Options
- AThe magnitude of normal force acting on the rod at point A is mg 2 .
- BThe magnitude of normal force acting on the rod at point A is mg 2 .
- CThe tension in the string A B is mg 2 [ + a c ^2 ]
- DThe tension in the string AB is mg 2 [ + a c cosec ^2 ]
Correct answer
C. The tension in the string A B is mg 2 [ + a c ^2 ]
Step-by-step solution
For unit length of wire, F _ e = E electric force = 2 4 ₀ = ^2 2 ₀ excess charge per unit length of wire F _ m ₀ I ^2 2 t magnetic force According to given question aligned & F _ c = F _ m & ^2 2 ₀ = ₀ I ^2 2 & ( 1 )^2= 1 ₀ ₀ & ( n 20 ₀ ~V V R )^2= 1 ₀ ₀ & R = ₀ ₀ ( 20 )=360 aligned