1. Potential of the electrons, V = 30 kV = 3 x 104 V Hence, energy of the electrons, E = 3 x 104 eV Where, e = Charge on an electron = 1.6 x 10⁻19 C Ans (a). Maximum frequency produced by the X-rays = ν The energy of the electrons is given by the relation: E = hν Where, h = Planck’s constant = 6.626 xRead more

    Potential of the electrons, V = 30 kV = 3 x 104 V

    Hence, energy of the electrons, E = 3 x 104 eV Where,

    e = Charge on an electron = 1.6 x 10⁻19 C

    Ans (a).
    Maximum frequency produced by the X-rays = ν

    The energy of the electrons is given by the relation: E = hν

    Where, h = Planck’s constant = 6.626 x 10⁻34 Js

    Therefore ,  ν= E/h = (1.6 x 10⁻19) x (3 x 104) /(6.626 x 10⁻34)

    = 7.24 x 10¹⁸ Hz

    Hence, the maximum frequency of X-rays produced is 7.24 x 1018 Hz.

    Ans (b).

    The minimum wavelength produced by the X-rays is given as:

    λ =c/ν = (3 x 108) /(7.24 x 1018)

    =4.14 x 10⁻⁻¹¹ m =0.0414 nm

    Hence, the minimum wavelength of X-rays produced is 0.0414 nm.

     

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  2. Room temperature, T = 27°C Resistance of the heating element at T, R = 100Ω Let T₁ is the increased temperature of the filament. Resistance of the heating element at T₁, R₁ = 117 Ω Temperature co-efficient of the material of the filament, α= 1.70 x 10⁻⁴ °C-1 α is given by the relation ,α =(R₁-R)/R (Read more

    Room temperature, T = 27°C

    Resistance of the heating element at T, R = 100Ω

    Let T₁ is the increased temperature of the filament.

    Resistance of the heating element at T₁, R₁ = 117 Ω

    Temperature co-efficient of the material of the filament,

    α= 1.70 x 10⁻⁴ °C-1

    α is given by the relation ,α =(R₁-R)/R (T₁-T)

    Therefore , T₁-T = (R₁-R )/R α

    T₁-27= (117-100 )/100(α 1.70 x 10⁻⁴)

    T₁- 27 = 1000

    T₁ = 1000+27 = 1027 °C

    Therefore, at 1027°C, the resistance of the element is 117 Ω.

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  3. Ans (a). There are three resistors of resistances, R₁ = 2 Ω, R2 = 4 Ω, and R3 = 5 Ω They are connected in parallel. Hence, total resistance (R) of the combination is given by, 1/R =1/R₁ + 1/R2 +1/R3 = 1/2 + 1/4 + 1/5 = (10+5+4 )/20 = 19/20 Therefore R = 20/19 Ω Therefore, total resistance of the comRead more

    Ans (a).
    There are three resistors of resistances,

    R₁ = 2 Ω, R2 = 4 Ω, and R3 = 5 Ω

    They are connected in parallel. Hence, total resistance (R) of the combination is given by,

    1/R =1/R₁ + 1/R+1/R3

    = 1/2 + 1/4 + 1/5 = (10+5+4 )/20 = 19/20

    Therefore R = 20/19 Ω

    Therefore, total resistance of the combination is 20/19 Ω.

    Ans (b).

    Emf of the battery, V = 20 V

    Current (I₁) flowing through resistor R₁ is given by,

    I₁ =V/R₁ = 20/2 =10 A

    Current (I2) flowing through resistor R2 is given by,

    I2 =V/R2= 20/4 = 5A

    Current (I3) flowing through resistor R3 is given by,

    I3=V/ R3 =20/5 =4 A

    Total current, I = I₁ + I2 + I3 = 10 + 5 + 4 = 19 A

    Therefore, the current through each resister is 10 A, 5 A, and 4 A respectively and the total current is 19 A.

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  4. Ans (a). Three resistors of resistances 1 Ω, 2 Ω, and 3Ω are combined in series. Total resistance of the combination is given by the algebraic sum of individual resistances. Total resistance = l + 2 + 3 = 6Ω Ans (b). Current flowing through the circuit = I Emf of the battery, E = 12 V Total resistanRead more

    Ans (a).

    Three resistors of resistances 1 Ω, 2 Ω, and 3Ω are combined in series. Total resistance of the combination is given by the algebraic sum of individual resistances. Total resistance = l + 2 + 3 = 6Ω

    Ans (b).

    Current flowing through the circuit = I

    Emf of the battery, E = 12 V

    Total resistance of the circuit, R = 6 Ω

    The relation for current using Ohm’s law is,

    I =E/R

    =12/6 =2 A

    Potential drop across 1 Ω resistor = V₁

    From Ohm’s law, the value of V₁ can be obtained as

    V₁ = 2 x 1= 2 V                                                                                … (i)

    Potential drop across 2 Ω resistor = V2

    Again, from Ohm’s law, the value of V2 can be obtained as

    V2 = 2 x 2= 4 V                                                                                … (ii)

    Potential drop across 3 Ω resistor = V3

    Again, from Ohm’s law, the value of V3 can be obtained as

    V3 = 2 x 3= 6 V … (iii)

    Therefore, the potential drop across 1 Ω, 2 Ω and 3 Ω resistors are 2 V, 4 V, and 6 V respectively.

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  5. Emf of the battery, E = 10 V Internal resistance of the battery, r = 3fi Current in the circuit, I = 0.5 A Resistance of the resistor = R The relation for current using Ohm's law is, I = E/(R+r) R+r =E/I= 10/0.5 =20 Ω Therefore ,R =20-3 = 17 Ω Terminal voltage of the resistor = V According to Ohm'sRead more

    Emf of the battery, E = 10 V

    Internal resistance of the battery, r = 3fi

    Current in the circuit, I = 0.5 A

    Resistance of the resistor = R

    The relation for current using Ohm’s law is,

    I = E/(R+r)

    R+r =E/I= 10/0.5 =20 Ω

    Therefore ,R =20-3 = 17 Ω

    Terminal voltage of the resistor = V

    According to Ohm’s law,

    V = IR = 0.5 x 17 = 8.5 V

    Therefore, the resistance of the resistor is 17 Q and the terminal voltage is 8.5 V.

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