A diode detector is used to detect and amplitude modulated wave of 60% modulation by using a condenser of capacity 250 pF in parallel with a load resistance 100 k$$\Omega$$. Find the maximum modulated frequency which could be detected by it.
Red light of wavelength 5400 $$\mathop A\limits^o $$ from a distant source falls on a slit 0.80 mm wide. Calculate the distance between first two dark bands on each side of central bright band in the diffraction pattern observed on a screen place 1.4 m from the slit.
A circular loop of radius 0.3 cm lies parallel to a much bigger circular loop of radius 20 cm. The centre of the small loop on the axis of the bigger loop. The distance between their centres is 15 cm. If a current of 20 A flows through the smaller loop, then the flux linked with bigger drop is
In the adjoining circuit diagram, the readings of ammeter and voltmeter are 2 A and 120 V, respectively. If the value of R is 75$$\Omega$$, then the voltmeter resistance will be