Television reports showed students protesting against AAP leader, who is being probed in alleged fake law degree case, for defaming the varsity's name.
Students raised slogans against the former Delhi minister and even threw eggs at him.
Tomar was earlier taken to the neighbouring Munger district for interrogation in connection with the ongoing probe into his alleged fake law degree, police said.
"A Delhi Police team brought arrested minister Tomar to Munger for interrogation into his fake law degree," said a district police official in Munger, about 170 km from Patna.
Police said Tomar was grilled at Hotel Rajhans in Munger.
"Delhi Police team have collected evidences in the case."
He was arrested last Tuesday following an investigation into a complaint by the Bar Council of Delhi that he had obtained a fake law degree from the Institute of Legal Studies College in Munger.
Tomar currently is in police remand for four days.