Physics Test - 1

The core of the transformer is laminated to reduce energy losses as they interfere with the efficient transfer of energy from the primary coil to the secondary one. The eddy currents cause energy to be lost from the transformer as they heat up the core meaning that electrical energy is being wasted as heat.

Since the linear momentum of the system is constant. The linear moment of each particle won’t remain constant.

• The total linear momentum of the system remains constant.
• The total energy of the system will remain constant according to the conservation of energy principle.
  
• According to the definition of elastic collision, the total kinetic energy of the system remains constant.

weight-the measurement of the gravitational pull on an object is its weight.

Given-

Length $l=3 m$

Area of cross-section $A=1.7\times {10}^{-6} m^2$

Resistance $R=3\times {10}^{-2} \Omega$

According to the formula-

$R=\rho \frac{l}{A}$   where $\rho$ is the resistivity of the wire

$\rho =\frac{R\times A}{l}$

$\rho =\frac{3\times {10}^{-2}\times 1.7\times {10}^{-6}}{3}$

$\rho =1.7\times {10}^{-8} \Omega m$

If the gravitational acceleration at any place is doubled, then the weight of body will be 2g.

Gravitational acceleration (symbolized g) is an expression used in physics to indicate  intensity of a gravitational field. It is expressed in meters per second squared (m/s ² ). ... Conversely, a free-falling object near the earth's surface gains downward speed at a rate of 9.8 m/s ² 

For momentum to be constant, the mass and velocity of a body should be constant.

Momentum $p=$ Mass $m\times$ Velocity $v$

$p=$ constant $\times$ constant

On multiplying two constants, we get a constant.

$p=$ constant

\({v}_{{c}}=3 {v}\)

\({R}_{{c}}=3000 \Omega\)

\({B}=100\)

\({I}_{{c}}=\frac{{V}_{{c}}}{{R}_{{C}}}=\frac{3}{3000}=10^{-3} {~A}\)

\({I}_{{b}}=\frac{{I}_{{c}}}{{B}}=\frac{{1 0}^{-3}}{{1 0 0}}=10^{-5} {A}\)

\({V}_{{b}}={I}_{{b}} {R}_{{b}}={1 0}^{-5} \times {2 0 0 0}={2} \times {1 0}^{-2} {V}\)

Voltage gain \(=\frac{{V}_{{c}}}{{V}_{{b}}}=\frac{3}{2 \times 10^{-2}}=150\)

Power gain \(= B\) × voltage gain \(=100 \times 150\)

\(={1 5 0 0 0}\)

When a missile is launched with a velocity less than the escape velocity of the earth, the sum of its kinetic energy and potential energy is negative.

When the fan is turned on, it circulates the air, which evaporates the sweat on our body. This creates a cool feeling and we feel comfortable.

Piezometers are used to measure the pore water pressure in soil. The piezometer tip is equipped with an electronic device known as a pressure transducer that can measure the water pressure. The piezometer tip is backfilled with a filter sand.