4. When a car is approaching the observer, the frequency of horn is 100Hz. After passing the observer, it is 50 Hz. If the observer moves with the car, the frequency will be Ha where x = 5. 6. A composite parallel plate capacitor is made up to two different dielectric materials with different thickness (t and t) as shown in figure. The two different dielectric materials are separated by a conducting foil F. The voltage of the conducing foil is _ V. &,3;t, 0.5mm = 4;t, =1mm 812 Resistances are connected in a meter bridge circuit as shown in the figure. The balancing length 2 is 40cm. Now as unknown resistance x is connected in A series with P and new balancing length is found to be 80cm measured from the same end. Then the value of x will be Q2. = P=402 () E K 3 100 V