Answer:
5 N
Explanation:
The formula that you've to use to find the force is :
Force = Mass × Acceleration
They have already given that,
m = 2.5 kg
a = 2 ms⁻²
Let us find now.
F = m a
F = 2.5 kg × 2 ms⁻²
F = 5 N
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When the mass of the spring changed from 0.2kg to 0.1kg, the time period changed from 1 sec to 0.5 seconds
<u>Explanation:</u>
Given-
Mass, m1 = 0.2kg
Time period, T1 = 1s
m2 = 0.1 kg
T2 = ?
We know,
where,
T = Time period
m = mass
k = spring constant
From the equation, we can see that T is directly proportion to the square root of mass, m
T ∝ √m
So,
If m1 = 0.2kg , T1 = 1s and m2 = 0.1kg
The T2 would be:
Therefore, when the mass of the spring changed from 0.2kg to 0.1kg, the time period changed from 1 sec to 0.5 seconds
Answer:
The potential difference between the plates is 8 V.
Explanation:
Given that,
Area of plates = 0.40 m²
Charge 
Distance = 4.0 cm
We need to calculate the electric field
Using for formula of electric field
Where, q = charge
A = area
Put the value into the formula
We need to calculate the potential difference between the plates
Using formula of potential difference
Where, E = electric field
d = distance
Put the value into the formula
Hence, The potential difference between the plates is 8 V.
Answer:
Electric field magnitude
E = K/qd
Where
K = kinetic energy of electron
d = electron distance
q = charge
Explanation:
Given the relationship between workdone and energy
Work-energy theorem:
Net workdone = Energy change
W = ∆E
In this case
W = ∆K.E
And,
∆K.E = K(final) - K(initial)
To stop the kinetic energy | K(final) = 0
K(initial) = K (given)
∆K.E = 0 - K = -K
Let the electric force on the electron has magnitude F.
And
W = -Fd = ∆K.E = -K
-Fd = -K
F = K/d .....1
The magnitude of the electric field E that can stop these electron in a distance d:
E = F/q ......2
Where q is the charge on electron.
substituting equation 1 to 2
E = (K/d)/q = K/qd
E = K/qd
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.
