What Is the Coefficient of Performance for a Carnot Engine Run as a Heat Pump?

[itryphysics]

Homework Statement

An ideal (Carnot) engine has an efficiency of 50 %
If it were possible to run it backward as a heat pump, what would be its coefficient of performance?

Homework Equations

COP = (T_L) / (T_H - T_L )

The Attempt at a Solution

no temperatures are given. I just know that since e = 1 - T_L / T_H then T_L / T_H is 0.5 since the efficiency is 50%

 

[Redbelly98]

Homework Statement

An ideal (Carnot) engine has an efficiency of 50 %
If it were possible to run it backward as a heat pump, what would be its coefficient of performance?

Homework Equations

COP = (T_L) / (T_H - T_L )

The Attempt at a Solution

no temperatures are given. I just know that since e = 1 - T_L / T_H then T_L / T_H is 0.5 since the efficiency is 50%

Okay, since T_L is 0.5 T_H what does that give for COP?