A_centrifugal_pump_which_circulates_a_hot_liquid_metal_at_500_degree_Celsius_is_driven_by_a_3600_rpm_electric_motor._The_motor_is_coupled_to_the_pump_impeller_by_a_horizontal_steel_shaft_of_dia_25_mm._Let_us_assume_the_motor_temperature_as_60_degree_Celsius_with_the_ambient_air_at_25_degree_Celsius,_what_length_of_shaft_should_be_specified_between_the_motor_and_the_pump?_It_may_be_presumed_that_the_thermal_conductivity_of_the_shaft_material_is_35W/m_K_and_that_the_convective_film_coefficient_between_the_steel_shaft_and_the_ambient_air_is_15.7W/square_m_K$

• A. 38.96 cm
• B. 54.76 cm
• C. 23.76 cm
• D. 87.43 cm