n DC generator , the generated emf at load is less than that at no-load due to:*Voltage dropArmature reactionInterpolesArmature resistance

In a DC generator, the generated EMF (Electromotive Force) at load is less than that at no-load due to several reasons:

1. Voltage Drop: When the generator is loaded, the current through the armature increases. This increased current causes a voltage drop across the armature resistance, which reduces the net voltage available at the terminals.

2. Armature Reaction: The magnetic field produced by the current in the armature windings can interact with the main field, causing a distortion known as armature reaction. This can cause a reduction in the net magnetic field, and hence, a reduction in the generated EMF.

3. Interpoles: Interpoles are small poles placed between the main poles to counteract the effect of armature reaction. However, they can also cause a slight reduction in the net magnetic field, and hence, a reduction in the generated EMF.

4. Armature Resistance: The resistance of the armature windings also causes a voltage drop, which reduces the net voltage available at the terminals.

So, all these factors contribute to the reduction of the generated EMF at load in a DC generator.