Properties of Laplace Transformations - Question Bank

1. The property L{f(t)/t} = ∫<0xE2><0x82><0x9B> F(σ) dσ is valid when:
A) lim<0xE2><0x82><0x9B>→∞ F(σ) exists and is 0
B) lim<0xE2><0x82><0x9B>→∞ F(σ) exists
C) F(s) is finite
D) f(t)/t is continuous
2. If L{f(t)} = F(s), then L{∫₀ᵗ f(τ) dτ} is:
A) F(s)/s
B) sF(s)
C) F(s+a)
D) F(s-a)
3. What is the Laplace transform of t*e^(at)?
A) 1/(s-a)^2
B) 1/(s+a)^2
C) a/(s-a)^2
D) 1/(s-a)
4. The second shifting theorem states that if L{f(t)} = F(s), then L{f(t-a)u(t-a)} equals:
A) e^(-as)F(s)
B) e^(as)F(s)
C) F(s-a)
D) F(s+a)
5. If L{f(t)} = F(s), then L{t*f(t)} is given by:
A) -dF(s)/ds
B) dF(s)/ds
C) F(s)/s
D) sF(s)
6. The Laplace transform of e^(at)sin(ωt) is:
A) ω/((s-a)^2 + ω^2)
B) (s-a)/((s-a)^2 + ω^2)
C) ω/((s+a)^2 + ω^2)
D) (s-a)/((s-a)^2 - ω^2)
7. What is the Laplace transform of e^(at)cos(ωt)?
A) (s-a)/((s-a)^2 + ω^2)
B) ω/((s-a)^2 + ω^2)
C) (s+a)/((s+a)^2 + ω^2)
D) (s-a)/((s-a)^2 - ω^2)
8. The property L{∫₀ᵗ f(τ) dτ} = F(s)/s means that integration in the time domain corresponds to division by ____ in the s-domain.
A) s
B) s^2
C) 1/s
D) a
9. If L{f(t)} = F(s), then L{f(t)/t} is given by:
A) ∫<0xE2><0x82><0x9B> F(σ) dσ
B) ∫₀<0xE2><0x82><0x9B> F(σ) dσ
C) F(s)/s
D) sF(s)
10. The Laplace transform of the unit ramp function t is:
A) 1/s^2
B) 1/s
C) 2/s^3
D) s
11. What is L{t^n}? (n is a non-negative integer)
A) n!/s^(n+1)
B) n/s^n
C) (n+1)!/s^n
D) 1/s^(n+1)
12. The Laplace transform of the convolution of two functions f(t) and g(t) is:
A) F(s)G(s)
B) F(s) + G(s)
C) F(s)/G(s)
D) F(s) - G(s)
13. If L{f(t)} = F(s), what is L{f''(t)}?
A) s^2F(s) - sf(0) - f'(0)
B) sF(s) - f(0)
C) F(s)/s^2
D) s^2F(s)
14. The property relating L{f(t)} = F(s) to L{e^(at)f(t)} is the:
A) First Shifting Theorem
B) Second Shifting Theorem
C) Frequency Differentiation Property
D) Time Differentiation Property
15. What is the Laplace transform of cosh(at)?
A) s/(s^2 - a^2)
B) a/(s^2 - a^2)
C) s/(s^2 + a^2)
D) 1/(s-a)
16. The Laplace transform of t*f(t) is given by:
A) -dF(s)/ds
B) dF(s)/ds
C) F(s)/s
D) sF(s)
17. If L{f(t)} = F(s), then L{f(at)} is:
A) (1/a)F(s/a)
B) aF(as)
C) F(s/a)
D) F(as)
18. What is the Laplace transform of t^3?
A) 6/s^4
B) 3/s^4
C) 6/s^3
D) 1/s^4
19. The Laplace transform of the integral ∫₀ᵗ g(τ) dτ is:
A) G(s)/s
B) sG(s)
C) G(s-a)
D) G(s)/a
20. If L{f(t)} = F(s), what is L{f'(t)}?
A) sF(s) - f(0)
B) sF(s)
C) F(s)/s
D) F(s) - f(0)
21. The Laplace transform of t*e^(at) is found using:
A) Multiplication by t property and First Shifting Theorem
B) Second Shifting Theorem
C) Division by t property
D) Convolution Theorem
22. If L{f(t)} = F(s), then L{f(t-a)u(t-a)} is:
A) e^(-as)F(s)
B) e^(as)F(s)
C) F(s-a)
D) F(s+a)
23. What is the Laplace transform of e^(-at)?
A) 1/(s+a)
B) 1/(s-a)
C) 1/s
D) a/s
24. The Laplace transform of t^2 is:
A) 2/s^3
B) 1/s^3
C) 2/s^2
D) 1/s^2
25. If L{f(t)} = F(s), then L{f(t)/t} is:
A) ∫<0xE2><0x82><0x9B> F(σ) dσ
B) ∫₀<0xE2><0x82><0x9B> F(σ) dσ
C) F(s)/s
D) sF(s)
26. What is the Laplace transform of the derivative of f(t), f'(t), given the initial condition f(0)?
A) sF(s) - f(0)
B) F(s)/s
C) sF(s)
D) F(s) - f(0)
27. The Laplace transform of t*sin(ωt) can be found using the property:
A) Multiplication by t
B) First Shifting Theorem
C) Division by t
D) Convolution
28. If L{f(t)} = F(s), then L{∫₀ᵗ f(τ) dτ} is:
A) F(s)/s
B) sF(s)
C) F(s+a)
D) F(s-a)
29. The property L{e^(at)f(t)} = F(s-a) is known as the:
A) First Shifting Theorem
B) Second Shifting Theorem
C) Frequency Differentiation Property
D) Time Differentiation Property
30. If L{f(t)} = F(s), what is the Laplace transform of f(t-a)u(t-a)?
A) e^(-as)F(s)
B) e^(as)F(s)
C) F(s-a)
D) F(s+a)
31. What is the Laplace transform of the Dirac delta function δ(t)?
A) 1
B) 1/s
C) s
D) 0
32. If f(t) is a unit step function, L{f(t)} is:
A) 1/s
B) 1
C) s
D) 1/s^2
33. The Convolution Theorem states that if L{f(t)} = F(s) and L{g(t)} = G(s), then L{f(t) * g(t)} (where * denotes convolution) is:
A) F(s)G(s)
B) F(s) + G(s)
C) F(s)/G(s)
D) F(s) - G(s)
34. The Laplace transform of a periodic function f(t) with period T is given by:
A) (1 / (1 - e^(-sT))) * ∫₀ᵀ e^(-st) f(t) dt
B) ∫₀ᵀ e^(-st) f(t) dt
C) (1 / (1 + e^(-sT))) * ∫₀ᵀ e^(-st) f(t) dt
D) T * ∫₀ᵀ e^(-st) f(t) dt
35. If L{f(t)} = F(s), then the Laplace transform of t*f(t) is:
A) -dF(s)/ds
B) dF(s)/ds
C) F(s)/s
D) sF(s)
36. The property that L{∫₀ᵗ f(τ) dτ} = F(s)/s implies that the Laplace transform of an integral corresponds to division by:
A) s
B) s^2
C) 1/s
D) a
37. If L{f(t)} = F(s), what is L{f(at)}?
A) (1/a)F(s/a)
B) aF(as)
C) F(s/a)
D) F(as)
38. The Laplace transform of t^n, where n is a non-negative integer, is:
A) n!/s^(n+1)
B) n/s^n
C) (n+1)!/s^n
D) 1/s^(n+1)
39. What is the Laplace transform of t?
A) 1/s^2
B) 1/s
C) 2/s^3
D) s
40. L{sinh(at)} is equal to:
A) a/(s^2 - a^2)
B) s/(s^2 - a^2)
C) a/(s^2 + a^2)
D) 1/(s+a)
41. The Laplace transform of the hyperbolic cosine, cosh(at), is:
A) s/(s^2 - a^2)
B) a/(s^2 - a^2)
C) s/(s^2 + a^2)
D) 1/(s-a)
42. What is the Laplace transform of sin(ωt)?
A) ω/(s^2 + ω^2)
B) s/(s^2 + ω^2)
C) ω/(s^2 - ω^2)
D) 1/s
43. L{cos(ωt)} is equal to:
A) s/(s^2 + ω^2)
B) ω/(s^2 + ω^2)
C) s/(s^2 - ω^2)
D) 1/s
44. The Laplace transform of e^(at) is:
A) 1/(s-a)
B) 1/(s+a)
C) 1/s
D) a/s
45. What is the Laplace transform of a constant 'a', i.e., L{a}?
A) a/s
B) a
C) a*s
D) 1/a
46. The property L{f(t)/t} = ∫<0xE2><0x82><0x9B> F(σ) dσ, where F(s) = L{f(t)}, is known as:
A) Division by t Property
B) Multiplication by t Property
C) Convolution Theorem
D) Change of Scale Property
47. If L{f(t)} = F(s), then L{t^n f(t)} is given by:
A) (-1)^n * d^n/ds^n [F(s)]
B) (d/ds)^n [F(s)]
C) n! * F(s)
D) F(s)/s^n
48. The Laplace transform of the integral of a function, L{∫₀ᵗ f(τ) dτ}, is related to L{f(t)} = F(s) by:
A) F(s)/s
B) sF(s)
C) F(s-a)
D) F(s)/a
49. What is the Laplace transform of f''(t) given L{f(t)} = F(s)?
A) s^2F(s) - sf(0) - f'(0)
B) sF(s) - f(0)
C) F(s)/s^2
D) s^2F(s)
50. If L{f(t)} = F(s), what is the Laplace transform of f'(t)?
A) sF(s) - f(0)
B) F(s)/s
C) sF(s)
D) F(s) - f(0)