The following signal V_i of peak voltage 8V is applied to the non-inverting terminal of an ideal Opamp. The transistor has V_BE = 0.7 V, $$\beta \, = \,100;$$ V_LED = 1.5 V, V_CC = 10V and -V_CC = -10V.

The number of times the LED glows is ______.

An ideal opamp has voltage source V₁, V₃, V₅, ......, V_N-1, connected to the non- inverting input and V₂, V₄, V₆, .....V_N connected to the inverting input as shown in the figure below (+V_CC= 15 volt, -V_CC = -15 volt). The voltage V₁, V₂, V₃,V₄, V₅, V₆ ....... are 1, -1/2, 1/3, -1/4, 1/5, -1/6, .... volt, respectively. As N approaches infinity, the output voltage (in volt) is _______

A p-i-n photo diode of responsivity 0.8A/W is connected to the inverting input of an ideal opamp as shown in the figure, +V_CC = 15V, - V_CC = -15V, Load resistor R_L = 10 k$$\Omega $$ . If 10$$\mu $$W of power is incident on the photodiode, then the value of the photocurrent (in $$\mu $$A) through the load is _____.

A super heterodyne receiver operates in the frequency range of 58 MHz – 68 MHz. The intermediate frequency f_1F and local oscillator frequency f_L0 are chosen such that f_1F $$\leq$$ f_L0.It is required that the image frequencies fall outside the 58 MHz – 68 MHz band. The minimum required f_1F (in MHz) is ___________.