A rod (length = l) is rotating about it s center with a speed 'w' at temperature to . If the temperature is increased to $\;t_{0}+\bigtriangleup t\;$ , the new speed of rotation is -

Question

$(a)\;w(1+2 \alpha \bigtriangleup t)\qquad(b)\;w(1+ \alpha \bigtriangleup t)\qquad(c)\;\large\frac{w}{w(1+2 \alpha \bigtriangleup t)}\qquad(d)\;\large\frac{w}{w(1+ \alpha \bigtriangleup t)}$