Embibe Experts Solutions for Chapter: Current Electricity, Exercise 1: Goa Board-2018

The figure shows a portion of a circuit. The magnitude and direction of the current ‘I’ in section ‘PQ’ of the wire is :

 The circuit diagram shows a potentiometer for determining the internal resistance of cell ${\epsilon }_1$ With the key ‘K’ open, the balancing length obtained is AD :

 If the resistance $R_1$ is increased, towards which end of the wire will the balance point ‘D’ shift ? Why ?

 The circuit diagram shows a potentiometer for determining the internal resistance of cell ${\epsilon }_1$ With the key ‘K’ open, the balancing length obtained is AD :

If the key ‘K’ is closed, towards which end of the wire will the balance point ‘D’ shift ? Why ?

In the given circuit diagram the resistance $R_1=8\Omega ,R_2=4 \Omega$. The circuit is powered by a source of emf $E = 48 V$:

What is the value of the current in the circuit, when the contact 1 is in use and key K is open ?

In the given circuit diagram the resistance $R_1=8\Omega ,R_2=4 \Omega$. The circuit is powered by a source of emf $E = 48 V$:

If the contact is moved from 1 to 2 and key K is closed, the total current in the circuit changes by 6A. Calculate $R_3$ .

Which mode of propagation uses ionosphere to reflect the transmitted signals from the Earth ? State other two modes of propagation.

The circuit diagram shows a transistor as an amplifier :

What is the phase difference between the input and the output voltage ?

The circuit diagram shows a transistor as an amplifier :

How does the collector current change when the base current increases ?