In Burglar alarm, LDR acts an AND gate.
Answer: C
Explanation
The LDR is light dependent resistor. The principle used in the working of LDR is that the resistance is inversely proportional to the intensity of light falling on the diode.
In burglar alarm, LDR diode is combined with an IC 555.
Normally an LED source is made to be incident on the LDR diode with same intensity such that the resistance will be maintained constant.
As the LDR is connected with IC, the voltage will be high when light is falling on the diode.
The IC will give only two output states that is high and low. This confirms that LDR in burglar alarm act as AND gate.
As the thief enters and crosses the LED light, the intensity of the light falling on the diode will decrease leading to decrease in the voltage which will cause the alarm to beep.
Answer:
Conductors and insulators are both important in the field of electronics. Electrical conductors allow electric current to flow easily because of the make up of their atoms. In a conductor, the outer electrons of the atom are loosely bound and can freely move through the material when an electric charge is applied.
Explanation:
B is the correct answer because an object moving ten north m/s will turn into 15m/s which as you can tell is accelerating.
Answer:
x = 54.15 meters between the balloons horizontally.
Explanation:
Hence, vertical distance between balloons is 12.8 meters.
y= 61-48.2 = 12.2 m
A right-angle triangle is formed with,
angle θ = 13.3 degrees
opposite (y) = 12.8
adjacent (x) = ?
Now by putting the values in the above equation.
x = 54.15 meters between the balloons horizontally.
Answer:
B. 560 J
J. 1.2 m
Explanation:
v = Final velocity = 0
u = Initial velocity = 4 m/s
= Coefficient of friction = 0.7
m = Mass of runner = 70 kg
g = Acceleration due to gravity = 
Kinetic energy is given by
The mechanical energy lost is 560 J
Acceleration is given by
From kinematic equations we get
The runner slides for 1.2 m
