Step-by-step explanation:
It is given that,
Total weight of the piston, W = F = 70 N
Area of the piston,
![a=5* 10^(-4)\ m^2](https://img.qammunity.org/2020/formulas/physics/high-school/g4pnowme3mqoadh78qvqs6crdwzjl9rx74.png)
Let P is the pressure exerted on the piston by the gas. The force per unit area is called the pressure exerted pressure of the gas. Mathematically, it is given by :
![P=(F)/(A)](https://img.qammunity.org/2020/formulas/physics/college/w6dmjhgoa2nqzut32hmrr8jf5dlyl9vj0l.png)
![P=(70\ N)/(5* 10^(-4)\ m^2)](https://img.qammunity.org/2020/formulas/physics/high-school/gwdfq3jwwuo71r7o1nr81ngkkbcq2y9i5s.png)
![P=1.4* 10^5\ Pa](https://img.qammunity.org/2020/formulas/physics/high-school/pcrxp3mnrcmxz9nauhfvdsfkmlj9mcxalj.png)
We know that the atmospheric pressure is given by :
![P_o=1.013* 10^5\ Pa](https://img.qammunity.org/2020/formulas/physics/high-school/1kpucwdpfvusv3z8g2sowiqpnckh0v9ei7.png)
So, the pressure is given by :
![p=P+P_o](https://img.qammunity.org/2020/formulas/physics/high-school/ab5en6rjkru2in8t1ykdpgik8tjqmjugrc.png)
![p=1.4* 10^5+1.013* 10^5](https://img.qammunity.org/2020/formulas/physics/high-school/j0106x33o3n6eew9emtzj7pn4xokfk2tlv.png)
![p=2.41* 10^5\ Pa](https://img.qammunity.org/2020/formulas/physics/high-school/87c3aveug9iit4w2t1afbn663ebajepvep.png)
Hence, this is the required solution.