Question Infinite Jump, how can i fix it? 3D enviroment.

My code works fine, the character has movement and jumps, but there is a problem.

When I press the jump button I can do it infinitely, how can I solve that?

Here is my code:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class PlayerMovement : MonoBehaviour
{

public float Speed = 1.0f;
public float RotationSpeed = 1.0f;
public float JumpForce = 1.0f;

private Rigidbody Physics;

void Start()
{
Cursor.lockState = CursorLockMode.Locked;
Cursor.visible = false;

Physics = GetComponent<Rigidbody>();
}

void Update()
{
//Movement
float horizontal = Input.GetAxis("Horizontal");
float vertical = Input.GetAxis("Vertical");

transform.Translate(new Vector3(horizontal, 0.0f, vertical) * Time.deltaTime * Speed);

//Camera Rotation
float rotationY = Input.GetAxis("Mouse X");

transform.Rotate(new Vector3(0, rotationY * Time.deltaTime * RotationSpeed, 0));

//Jump
if (Input.GetKeyDown(KeyCode.Space))
{
Physics.AddForce(new Vector3(0, JumpForce, 0), ForceMode.Impulse);
}

}
}