If present tense is being used then why is "ed" being used in the example given below - English - Verbs

Question

If present tense is being used then why is "ed" being used in
the example given below??????????In the topic helping verbs class
9, the second example given is -"The boy is punished by the teacher
"

Madhura Sarkar · Accepted Answer

Dear Student,
The verb has an 'ed' because the sentence is in the passive
voice
A verb can have 'ed' and yet be in the present tense, because
the helping verb('is' punished) is in the
present tense

If present tense is being used then why is "ed" being used in the example given below??????????In the topic helping verbs class 9, the second example given is -"The boy is punished by the teacher ".