Science
- If a charge of 420 C flows through a conducting wire in 5 minutes what is the value of the current? Current flowing through the conducting wire is I= Charge(Q)/Time (t) ⇒I=420/(5×60)=420/300=1.4 A Hence, the current flowing through the wire... 1
- When two resistors are connected in series, their effective resistance is 80 Ω. When they are connected in parallel, Let the two resistances be R₁ and R₂. Therefore, R₁ + R_(2 )= 80 Ω or, R_(1 )= 80 −R₂-R₂ .....(i) and 1/R₁+1/R₂=1/20 ⇒R₁R₂=20(R₁+R₂) As, R₁=... 1
- The resistance of a 1 m long nichrome wire is 6 Ω. If we reduce the length of the wire to 70 cm. Resistance of a wire is directly proportional to its length. Let R_(1 )and R₂ be the resistances of the nichrome wire at 100 cm (1 m) and 70... 1
- Three resistances x1 , x2 and x3 are connected in a circuit in different ways. x is the effective resistance 1. In this case, x₁,x_(2 )and x_(3 )are connected in series. 2. In this case, x₁ , x_(2 )and x_(3 )are connected in series. 3. In this case,... 1
- Resistances R1 , R2 , R3 and R4 are connected as shown in the figure. S1 and S2 are two keys. (i) The circuit for this case is shown below. R₄ is shunted by S_(2 ). Hence the Resistance of this combination will be practically zero R₁... 1
- The resistance of a conductor of length x is r. If its area of cross-section is a, what is its resistivity? We know R = ρ(L/A) ∴ Resistivity of a conductor, ρ = RA / L Here, L = x, R = r and A = a Therefore, ρ = ra / x The unit of resistivity is oh... 1
- Match the pairs ‘A’ Group ‘B’ Group 1. Free electrons a. V/ R 2. Current b. Increases the resistance in the circuit ‘A’ Group ‘B’ Group 1. Free electrons c. Weakly attached 2. Current a. V/ R 3. Resistivity d. VA/LI 4. Resistances in series b. Increases th... 1
- The following table shows current in Amperes and potential difference in Volts. V (Volts) I (Amp) (i). From Ohm's law, we have R=V/I V (volts) I (amp) R (ohm) 4 9 4/9=0.44 5 11.25 5/11.25=0.44 6 13.5 6/13.5=0.44 Therefore, average resista... 1
- Umesh has two bulbs having resistances of 15 Ω and 30 Ω . He wants to connect them in a circuit, but if he connects When Umesh connects the bulbs one at a time, the filaments of the bulbs get burnt. This means the heat energy generated in the filament is b... 1
- The following figure shows the symbols for components used in the accompanying electrical circuit. Ohm's law I=V/R can be proved with the help of above circuit. 1
- The accompanying figure shows some electrical appliances connected in a circuit in a house. 1. The appliances are in parallel connection. 2. The potential difference across each appliance should be same as they are connected in para... 1
- What is the law of conservation of energy? Energy can neither be created nor destroyed. It can be converted from one form into another. Thus, the total amount of energy in the univers... 1
- Into which form are the chemical energy stored in the exploding firecrackers converted to? Energy is transformed from one form to another. In the example stated, the exploding firecrackers convert the chemical energy stored in them... 1
- Ajay and Atul have been asked to determine the potential energy of a ball of mass m kept on a table as shown As seen from the picture, the heights of the ball with respect to Ajay and Atul are different. Also, given that the potential energy is rela... 1
- What is the potential energy? Potential energy of the object is the energy stored in it because of its specific state or position. 1
- What is kinetic energy? Kinetic energy is the energy that an object has because of its motion. The kinetic energy gained by the object is the work done by a force t... 1
- Define energy. What is its unit? Energy is the capacity of a body to perform work. Unit of energy is the same as that of work. In the SI system, the unit is joule, while in... 1
- Pravin has applied a force of 100 N on an object, at an angle of 600 to the horizontal. The object gets displaced Given here is θ=60⁰ and F=100N, while W= 400J , SO s=? Take the equation W = F s Cos θ Replace with values 400= 100 × s × ½ Hence, 400 / 100... 1
- Calculate the work done to take an object of mass 20 kg to a height of 10 m. (g = 9 8 m/s2) Suppose mass of the object (m) = 20 kg, while height (s) = 10 m given that g = 9.8 m/s² The value for F = mg = 20 × (-9 8) (Because the disp... 2
- Write about the National Physical Laboratory. The National Physical Laboratory, conceptualized in 1943 was situated in New Delhi and functions under the Council of Scientific and Industr... 1
- Give an example of where the work done by the gravitational force is zero. Take the example of an artificial satellite moving around the earth in a circular orbit. The work done by the gravitational force is zero as... 1
- With the force and the displacement specified, define the work done by the force. Work done by the force in the various scenarios are explained here: 1. The work done by the force is positive when the force and the displac... 2
- Define the relationship between joule and erg using the equation. It is given that 1 newton (1N) = 10⁵ dyne, while 1m = 10² cm. So, if Work= forces × displacement, then 1 joule = 1 newton × 1 m 1 joule = 10... 1
- Explain unit of work as per SI and CGS system. Given that, Work = Force × Displacement, the unit of force in SI system is newton (N), while the unit of displacement is metre (m). Hence, t... 1