An ac voltmeter using full -wave rectification and having a sinusoidal input has an ac sensitivity equal to
(1) 1.414 times dc sensitivity (2) dc sensitivity (3) 0.9 times dc sensitivity (4) 0.707 times dc sensitivity
(1) 1.414 times dc sensitivity (2) dc sensitivity (3) 0.9 times dc sensitivity (4) 0.707 times dc sensitivity