Torque τ = r · F · sin θ

Drag the sliders — only the part of the force perpendicular to the arm (F sin θ) turns the bolt.

Applied force F40 N
Distance from pivot r0.50 m
Angle θ (arm → force)90°
Torque τ
20.00 N·m
F sin θ
40.0 N
Lever arm r sin θ
0.50 m

At θ = 90° the whole force turns the bolt. At θ = 0° none of it does. Doubling r doubles the torque.