A thin copper rod 1. 0 m long has a mass of 0. 050 kg and is in a magnetic field of 0. 10 t. What minimum current in the rod is needed in order for the magnetic force to balance the weight of the rod?.

100 grams of molten lead (600°c) is used to make musket balls. if the lead shot is allowed to cool to room temperature (21°c), what is the change in entropy (in j/k) of the lead? (for the specific heat of molten and solid lead use 1.29 j/g⋅°c; the latent heat of fusion and the melting point of lead are 2.45 × 104 j/kg and 327°c, respectively.)