Physics
Bulb A rated 160 W, 40 V and Bulb B rated 40 W, 40 V are connected as shown in the diagram.
(a) Calculate the ratio V1 : V2.
(b) If the bulb A fuses, the current in the circuit remains the same. State True or False.
Related Questions
(a) One end of a plastic foot ruler is held tightly at the edge of a table and the other end is plucked. Name the vibrations produced in the ruler.
(b) Now the ruler is pushed inside partially and plucked again from its freе end. State with a reason whether the frequency of vibration increases or decreases.
Two persons A and B are standing in front of a cliff in the same line 170 m apart as shown in the diagram.
Person B fires the gun and hears the echo in 3 s. Then the person A standing in front of the person B fires the gun.
(Speed of sound in air is 340 m s-1)
(a) Calculate:
- the distance of the person B from the cliff.
- the minimum time in which B hears the gunshot fired by A.
(b) Fill in the blank.
The echo is softer (less loud) than the original sound due to the decrease in …………… [amplitude / frequency] of the wave.
The reverse side of a three-pin plug with incorrect connection of wires is shown in the diagram below.
(a) Identify the fault in the above connection.
(b) Mention a risk factor involved, if the user operates the appliance without correcting it.
(c) Will the appliance function in the present situation? (Yes or No)
In the combinations of resistors shown below. calculate:
(a) the resistance across AB when the switch S is open.
(b) the resistance across AB when the switch S is closed.