25. The work per unit volume to stretch the length by 1% of a wire with cross sectional area of 

25. The work per unit volume to stretch the length by 1% of a wire with cross sectional area of  1 mm² will be (Y=9×10¹¹ N/m²)

(a)   9×10¹¹  J                                       (b)  4.5×10⁷ J

(c)  9×10⁷ J                                      (d)  4.5 ×10¹¹ J

Answer-b

(10)