Answer
It will take 167 seconds to heat the soup.
Work Step by Step
We can find the mass of the soup as:
$m = \rho~V$
$m = (1000~kg/m^3)(250~mL)(\frac{10^{-6}~m^3}{1~mL})$
$m = 0.250~kg$
We can find the energy required to raise the temperature of the soup by $60^{\circ}C$:
$Q = mc~\Delta T$
$Q = (0.250~kg)(4186~J/kg~C^{\circ})(60^{\circ}C)$
$Q = 62,790~J$
We can find the time required for the heater to produce this amount of energy as:
$t = \frac{E}{P}$
$t = \frac{62,790~J}{375~W}$
$t = 167~seconds$
It will take 167 seconds to heat the soup.
